Latest

• Z chromosome

  A sex chromosome in certain animals, such as chickens, turkeys, and moths. In humans, males are XY and females XX, but in animals with a Z chromosome, males are ZZ and females are WZ.

• ZAP-70

  Zeta-chain-associated protein kinase 70. A member of the protein tyrosine kinase family, ZAP-70 is normally expressed in T cells and natural killer cells and has a critical role in the initiation of T-cell signaling. ZAP-70 is expressed in T cells and tumors of T-cell lineage. A high level of ZAP-70 expression appears restricted to T-cell […]

• Zebra

  ‘When you hear hoof beats, think of horses, not zebras.’ For example, when someone develops a mild transient cough, a virus infection is the most logical and likely cause, and tuberculosis is a zebra.

• Zygotic lethal gene

  A gene that is lethal (fatal) for the zygote, the cell formed by the union of a sperm (male sex cell) and an ovum (female sex cell). The zygote would normally develop into an embryo, as instructed by the genetic material within the unified cell. However, a zygotic lethal gene scotches prenatal development at its […]

• Zygote intrafallopian transfer (ZIFT)

  A technique in which a woman’s egg is fertilized outside the body, then implanted in one of her fallopian tubes. This technique is one of the methods used to overcome infertility, the inability of couples to produce offspring on their own. First, the egg and the male sperm needed to fertilize it are harvested. Then […]

• Zygote

  The cell formed by the union of a male sex cell (a sperm) and a female sex cell (an ovum). The zygote develops into the embryo following the instruction encoded in its genetic material, the DNA. The unification of a sperm and an ovum to form a zygote constitutes fertilization.

• Zygomycosis

  A potentially fatal, dangerous infection that is caused by various fungi from the class Zygomycetes. Zygomycosis is seen most often in patients who are already ill with diseases that suppress the immune system, such as AIDS, burn patients, patients taking corticosteroids, and those with poorly controlled diabetes. If unchecked, the fungal infection can spread to […]

• Zygomatic bone

  The part of the temporal bone of the skull that forms the prominence of the cheek. The zygomatic bone is also known as the zygomatic arch, the zygoma, the malar bone, the cheek bone and the yoke bone. The word “zygomatic” comes from the Greek “zygon” meaning a yoke or crossbar by which two draft […]

• Zygomatic arch

  The part of the temporal bone of the skull that forms the prominence of the cheek. The zygomatic arch is also known as the zygomatic bone, the zygoma, the malar bone, the cheek bone and the yoke bone. The word “zygomatic” comes from the Greek “zygon” meaning a yoke or crossbar by which two draft […]

• Zygoma

  The bone that forms the prominence of the cheek. Also known as zygomatic bone, zygomatic arch, malar bone, and yoke bone.

• Zoophobia

  An abnormal and persistent fear of animals. A phobia is an unreasonable fear that can cause avoidance and panic. Phobias are a relatively common type of anxiety disorder. Phobias can be treated with cognitive behavioral therapy using exposure and fear reduction techniques. In many cases, anti-anxiety or anti-depressant medication proves helpful, especially during the early […]

• Zoophilia

  A sexual disorder involving an erotic attraction to animals or an abnormal desire to have sexual contact with animals. Zoophilia is one form of paraphilia (deviant sexual behavior).

• Zooparasite

  A living parasite, such as a worm or protozoa.

• Zoonotic transfer

  Zoonosis; Zoonotic; Zoonotic disease.

• Zoonotic disease

  Any disease that is spread from animals to people. There are many known zoonotic diseases, some of them very familiar such as Lyme disease and malaria. Less familiar zoonotic diseases (beginning with the letters “a” and “b”) include alveolar hydatid disease (echinococcosis), ancylostoma infection (hookworm), ascariasis (intestinal roundworm infection), babesiosis (babesia infection), and baylisascaris infection […]

• Zoonotic

  anthrax ascariasis brucellosis plague echinococcosis Lassa fever listeriosis Lyme disease monkeypox psittacosis rabies salmonellosis trichinosis toxoplasmosis typhus and West Nile fever Zoonoses may appear suddenly and be relatively virulent, as illustrated by HIV which ignited the AIDS epidemic and the coronavirus responsible for the outbreak of SARS.

• Zoonosis

  An infection that is known in nature to infect both humans and lower vertebrate animals.

• Zone Diet

  The Zone diet is a weight loss plan based upon the idea that the right ratio of carbohydrates to proteins and fats can control levels of insulin in the bloodstream. Too much of the hormone, according to the diet’s developer Barry Sears, PhD, can increase fat storage and inflammation in the body. In his book […]

• Zona pellucida

  The strong membrane that forms around an ovum as it develops in the ovary. The membrane remains in place during the egg’s travel through the fallopian tube. To fertilize the egg, a sperm must penetrate the thinning zona pellucida. If fertilization takes place, the zona pellucida disappears, to permit implantation in the uterus.

• Zona

  1. A synonym for shingles. 2. Any zone or encircling area. 3. Any area with a specific boundary. Zona, Latin for a girdle, is a synonym for shingles because it can appear to girdle part of the body.

• Zomig

  Brand name for zolmitriptan, a triptan drug for the treatment of migraine.

• Zolmitriptan

  A triptan drug for the treatment of migraine. Marketed under the brand name Zomig.

• Zollinger-Ellison syndrome

  Tagamet] and ranitidine [Zantac]) and the proton pump inhibitors (for example, lansoprazole [Prevacid] and omeprazole [Prilosec]). The H2 antagonists block the action of histamine on stomach cells, thus reducing stomach acid production. The proton pump inhibitors also block the production of acid by the stomach cells. Proton pump inhibitors are more effective than H2 antagonists […]

• Zoll, Paul M.

  American cardiologist (1911-1999) and pioneer in the development of the cardiac monitor, pacemaker and defibrillator.

• ZNF9

  A gene that encodes a protein called zinc finger protein 9. An inherited mutation in ZNF9 causes type 2 myotonic dystrophy. One region of the ZNF9 gene has a particular 4-base-pair sequence, CCTG, that is normally repeated a few times. (Base pairs are the building blocks of DNA.) This region is called a tetranucleotide repeat. […]

• ZIP code, protein

  An informal name for a molecular cell biology system of signals or “address tags” that guide the movement of a protein within a cell. In more technical terms, protein ZIP codes* are molecular signals that direct the protein from the endoplasmic reticulum, where it is assembled, to the cytoplasm of the cell and into other […]

• Zinsser disease

  Also called Brill-Zinsser disease, recrudescence of epidemic typhus years after the initial attack. The agent that causes epidemic typhus (Rickettsia prowazekii) remains viable for many years and then when host defenses are down, it is reactivated causing recurrent typhus. The disease is named for the physician Nathan Brill and the great bacteriologist Hans Zinsser.

• Zinc sulfate

  A form of zinc that can be administered in eyedrops. Zinc sulfate is used in some types of eye tests.

• Zinc oxide

  An ingredient found in creams and ointments used to prevent or treat minor skin burns and irritation including sun burns and diaper rash.

• Zinc ointment

  A topical preparation that contains zinc and is applied to protect the skin from irritation or sunburn. Zinc ointment is also often the basis for commercial preparations for preventing diaper rash. It should not be used on skin that is already broken or irritated, however.

• Zinc finger

  A finger-shaped fold in a protein that permits it to interact with DNA and RNA. The fold is created by the binding of specific amino acids in the protein to a zinc atom. Zinc-finger proteins regulate the expression of genes as well as nucleic acid recognition, reverse transcription and virus assembly.

• Zinc excess

  Too much zinc can cause gastrointestinal irritation (upset stomach), interfere with copper absorption and cause copper deficiency, and (like too little zinc) cause immune deficiency. According to the National Academy of Sciences, the Recommended Dietary Allowance of zinc is 8 milligrams per day for women age 19+ years and 11 milligrams per day for men […]

• Zinc deficiency dermatitis and diarrhea

  Among the consequences of zinc deficiency, dermatitis (skin inflammation) and diarrhea are particularly prominent features. A genetic disease called acrodermatitis enteropathica in which there is impaired zinc uptake from the intestine is, in fact, characterized by the simultaneous presence of dermatitis (skin inflammation) and diarrhea. The skin on the cheeks, elbows and knees and the […]

• Zinc deficiency

  According to the National Academy of Sciences, the Recommended Dietary Allowance of zinc is 8 milligrams per day for women age 19+ years and 11 milligrams per day for men age 19+ years. Food sources of zinc include meat including liver, eggs, seafood, nuts and cereal. Deficiency of zinc is associated with short stature, anemia, […]

• Zinc

  A mineral that is essential to the body and is a constituent of many enzymes that permit chemical reactions to proceed at normal rates. Zinc is involved in the manufacture of protein (protein synthesis) and in cell division. Zinc is also a constituent of insulin, and it is involved with the sense of smell. Food […]

• ZIFT

  Stands for zygote intrafallopian transfer, a method used to treat infertility in which an egg fertilized in vitro (outside the body) is placed into a woman’s fallopian tube. This technique is one used to overcome infertility, the inability of couples to produce offspring on their own. The egg and the male sperm needed to fertilize […]

• Zhitai

  One of the three major preparations of red yeast rice, a tradition Chinese medicine now used to lower cholesterol.

• Zenker diverticulum

  The most common type of outpouching in the esophagus, due to increased pressure causing the mucous membrane of the esophagus to herniate through a defect in the wall of esophagus. Zenker diverticuli are usually located in the posterior hypopharyngeal wall. Small Zenker diverticuli may not cause symptoms but larger ones may collect food and obstruct […]

• Zellweger syndrome

  One of a group of related diseases called peroxisome biogenesis disorders (PBD), inherited conditions that damage myelin in the brain and also affect the metabolism of particular substances. Features include enlargement of the liver, high levels of iron and copper in the blood, and vision disturbances. It can be caused by mutations in a number […]

• Zeitgeber

  An environmental agent or event that provides the cue for setting or resetting a biological clock. To be synchronized with our environment, we need the input of Zeitgebers. The most important Zeitgeber in nature is light. Social factors, chemical factors and activity can also serve as Zeitgebers. Light is a so-called photic type Zeitgeber, whereas […]

• Y (in chemistry)

  The symbol for the element yttrium, an ultrarare metal named after Ytterby in southern Sweden. Yttrium has been used in certain nuclear medicine scans.

• Y (in genetics)

  The Y chromosome, the sex chromosome found in normal males, together with an X chromosome.

• Y chromatin

  A brilliantly fluorescent body seen under the microscope in cells containing a Y chromosome when the cells are stained with the dye quinacrine. Quinacrine lights up the Y chromosome more than other chromosomes.

• Yttrium Y 90 ibritumomab tiuxetan

  An anticancer therapy that is a combination of the radioisotope yttrium-90 and a monoclonal antibody to produce substances that locate and bind to cancer cells. Also called IDEC-Y2B8 monoclonal antibody.

• Yttrium

  A rare elemental metal. A radioactive form of yttrium is used in radiation therapy and some types of immunotherapy.

• Youth violence

  Violence involving young persons, typically children, adolescents, and young adults between the ages of 10 and 24. The young person can be the victim, the perpetrator, or both. Youth violence includes aggressive behaviors such as verbal abuse, bullying, hitting, slapping, or fistfighting. These behaviors have significant consequences but do not generally result in serious injury […]

• Youth

  The time between childhood and maturity.

• Yolk stalk

  most commonly as a finger-like protrusion from the small intestine known as Meckelis diverticulum. Found in 2 to 4 percent of people, Meckelis diverticulum may become inflamed (much like the appendix) and require surgical removal. Also known as the omphalomesenteric duct, umbilical duct, or vitelline duct.

• Yolk sac

  Not all yolk has to do with birds’ eggs. Human embryos have a yolk sac, too. The human yolk sac is a membrane outside the embryo that is connected by a tube (the yolk stalk) though the umbilical opening to the embryo’s midgut. The yolk sac serves as an early site for the formation of […]

• Yogurt

  A dairy product made by fermented milk with one or more bacterial cultures. It has been used to repopulate the normal bacterial flora of the intestines after antibiotic therapy and associated diarrhea and for treating and preventing vaginal yeast and bacterial infections.

• Yoga

  A relaxing form of exercise that was developed in India and involves assuming and holding postures that stretch the limbs and muscles, doing breathing exercises, and using meditation techniques to calm the mind. Yoga appears to have benefits for increasing physical flexibility and reducing internal feelings of stress. Yoga may be recommended as an alternative […]

• Yersiniosis

  Use separate cutting boards for meat and other foods. Carefully clean all cutting boards, counter-tops, and utensils with soap and hot water after preparing raw meat. Dispose of animal feces in a sanitary manner.

• Yersinia pestis

  The bacteria that causes the bubonic plague which in the year 541 (as the Black Death) and later in the Middle Ages decimated Europe. The effects of the plague are described in the nursery rhyme “We all fall down.” Y. pestis mainly infects rats and other rodents which are the prime reservoir for the bacteria. […]

• Yersinia enterocolitica

  Use separate cutting boards for meat and other foods. Carefully clean all cutting boards, counter-tops, and utensils with soap and hot water after preparing raw meat. Dispose of animal feces in a sanitary manner.

• Yersinia

  A group of bacteria that appear rod-like under the microscope and include Yersinia pestis (the cause of the bubonic and pneumonic plague), Yersinia entercolitic a (the cause of a disease called yersinosis), and Yersinia pseudotuberculosis (which causes a condition called mesenteric adenitis, particularly in immunocompromised patients). Both Y. entercolitica and Y. pseudotuberculosis have also been […]

• Yerba mate

  A stimulant beverage similar to tea, very popular in South America, brewed from the dried leaves and stemlets of a member of the holly family known botanically as Ilex paraguayensis. Despite claims to the contrary, Yerba mate does contain caffeine although the level is relatively low compared to coffee or tea. Yerba mate also contains […]

• Yellow jacket sting

  A sting from a yellow jacket (or other large stinging insects such as bees, hornets and wasps) can trigger allergic reactions ranging from local responses of limited duration to catastrophic general reactions which can be fatal. The susceptibility to severe reactions appears inherited. Avoidance and prompt treatment are essential. Immediate treatment is with adrenaline by […]

• Yellow jack

  1) The flag displayed from lazarettos, naval hospitals, and vessels in quarantine. 2) Synonym for yellow fever as, for example, in “…Fernando passed a few weeks recovering from a touch of yellow jack.”

• Yellow fever vaccination

  A live attenuated (weakened) viral vaccine for yellow fever. Yellow fever vaccination is recommended for people traveling to or living in the tropical areas in the Americas and Africa where yellow fever occurs. Because yellow fever vaccination is a live vaccine, it should not be given to infants or people with immune-system problems.

• Yellow fever

  “This disease was prevalent in the deep south, not just in the seaports. My grandparents lived through an epidemic of yellow jack in central Mississippi around 1900, and they were a long way from the seacoast.”) Today yellow fever is most common in tropical areas of Africa and the Americas. The virus of yellow fever […]

• Yellow enzymes

  A group of respiratory enzymes that catalyze reactions in the body permitting cells to respire, to breath, or in other word, to use oxygen. These biochemical reactions are termed oxidation-reduction reactions. The first yellow enzyme was discovered by the German biochemist Otto Heinrich Warburg (1883-1970), a pioneer in research on the respiration of cells, who […]

• Yellow enzyme, Warburg’s

  A key respiratory enzyme discovered by the German biochemist Otto Heinrich Warburg (1883-1970), a pioneer in research on the respiration of cells and the metabolism of tumors. Warburg’s yellow enzyme is a flavoprotein that catalyzes an oxidation-reduction reaction necessary for normal breathing (respiration) , in other words, use of oxygen by cells. Warburg won the […]

• Yeast vulvitis

  A yeast infection of the external genital organs of the female (the vulva). The vulva includes the labia, clitoris, and the entrance (the “vestibule”) to the vagina. Yeast vulvitis commonly goes together with yeast vaginitis, infection of the vagina by the fungus known as Candida. The common symptoms are itching, burning, soreness, pain during intercourse […]

• Yeast vaginitis

  Infection of the vagina by a fungus known as Candida, characteristically causing itching, burning, soreness, pain during intercourse and urination, and vaginal discharge. Yeast vaginitis occurs when new yeast are introduced into the vagina or there is an increase in the quantity of yeast in the vagina relative to the quantity of bacteria (as when […]

• Yeast syndrome

  The yeast Candida has been thought to cause a syndrome with a number of nonspecific problems including fatigue, loss of appetite, headache, short-attention span, depression and all manner of intestinal irregularities. There is no scientific evidence to support the existence of the yeast syndrome (also called the yeast connection).

• Yeast rash

  A slightly raised pink-to-red rash that is caused by proliferation of yeast, usually in a moist area such as the groin. Yeast rash is most common in infants, but it can also occur on the skin of older children and adults. Treatment involves keeping the affected area clean and dry and applying topical antifungal medication. […]

• Yeast genome

  All of the genetic information contained in yeast (Saccharomyces cerevisiae). The genomes of particular nonhuman organisms such as yeast have been studied for a number of reasons including the need to improve sequencing and analysis techniques. These nonhuman genomes also provide powerful sets of data against which to compare the human genome. For example, a […]

• Yeast infection

  Overgrowth of yeast can affect the skin (yeast rash), mouth (thrush), digestive tract, esophagus, vagina (vaginitis), and other parts of the body. Yeast infections occur most frequently in moist areas of the body. Although Candida albicans and other Candida yeasts are the most frequent offenders, other yeast groups are known to cause illness, primarily in […]

• Yeast diaper rash

  Infection in the diaper area of a baby that is caused by a yeast called Candida. Certain conditions, such as antibiotic use or excessive moisture, can upset the balance of microbes and allow an overgrowth of Candida. The infected skin is usually fiery red with areas that may have a raised red border.

• Yeast artificial chromosome (YAC)

  A vector (carrier) created and used in the laboratory to clone pieces of DNA. A YAC is constructed from the telomeric, centromeric, and replication origin sequences needed for replication in yeast cells. (The telomere is the end of the chromosome; the centromere is the chromosome region to which spindle fibers attach during cell division; and […]

• Yeast

  A group of single-celled fungi that reproduce by budding. Most yeast are harmless (some are used in baking and brewing). Yeast is commonly present on normal human skin and in areas of moisture, such as the mouth and vagina, usually without causing any problems. However, yeast can produce disease in people. For example, the yeast […]

• Yaws

  A chronic infectious disease that occurs commonly in the warm, humid regions of the tropics. Yaws is characterized by bumps on the skin of the face, hands, feet, and genital area. Almost all cases of yaws are in children under 15 years of age. The organism that causes yaws is a type of spirochete bacteria, […]

• Yawning

  Involuntary opening of the mouth with respiration, breathing first inward, then outward. Yawning is often caused by the power of suggestion. Repeated yawning may be a sign of drowsiness. It can also sometimes be a sign of depression.

• Yawn

  Involuntary opening of the mouth, accompanied by slowly breathing inward and then outward. Repeated yawning can be a sign of drowsiness, boredom, or depression. The yawn helps to open tiny air sacs (alveoli) in the lungs that can collapse during shallow breathing.

• Yard

  A measurement of length that is equal to 0.9 meters, 3 feet, or 36 inches.

• YAG laser surgery

  The use of a YAG (yttrium-aluminum-garnet) laser to do surgery. One use for a YAG laser in surgery is to punch a hole in the iris to relieve increased pressure within the eye from acute angle-closure glaucoma. In this type of glaucoma, there is a sudden (acute) increase in pressure in the anterior (front) chamber […]

• YAC

  YAC stands for yeast artificial chromosome, a vector (carrier) created and used in the laboratory to clone pieces of DNA. A YAC is constructed from the telomeric, centromeric, and replication origin sequences needed for replication in yeast cells. (The telomere is the end of the chromosome; the centromere is the chromosome region to which spindle […]

• Y. pestis

  Yersinia pestis, the bacteria that causes the bubonic plague which in the year 541 (as the Black Death) and later in the Middle Ages decimated Europe. The effects of the plague are described in the nursery rhyme “We all fall down.” Y. pestis mainly infects rats and other rodents which are the prime reservoir for […]

• Y-linked inheritance

  ASMTY (which stands for acetylserotonin methyltransferase), TSPY (testis-specific protein), IL3RAY (interleukin-3 receptor), SRY (sex-determining region), TDF (testis determining factor), ZFY (zinc finger protein), PRKY (protein kinase, Y-linked), AMGL (amelogenin), CSF2RY (granulocyte-macrophage colony-stimulating factor receptor, alpha subunit on the Y chromosome), ANT3Y (adenine nucleotide translocator-3 on the Y), AZF2 (azoospermia factor 2), BPY2 (basic protein on […]

• Y-linked gene

  ASMTY (which stands for acetyl serotonin methyltransferase), TSPY (testis-specific protein), IL3RAY (interleukin-3 receptor), SRY (sex-determining region), TDF (testis determining factor), ZFY (zinc finger protein), PRKY (protein kinase, Y-linked), AMGL (amelogenin), CSF2RY (granulocyte-macrophage colony-stimulating factor receptor, alpha subunit on the Y chromosome), ANT3Y (adenine nucleotide translocator-3 on the Y), AZF2 (azoospermia factor 2), BPY2 (basic protein […]

• Y-linkage

  ASMTY (which stands for acetyl serotonin methyltransferase), TSPY (testis-specific protein), IL3RAY (interleukin-3 receptor), SRY (sex-determining region), TDF (testis determining factor), ZFY (zinc finger protein), PRKY (protein kinase, Y-linked), AMGL (amelogenin), CSF2RY (granulocyte-macrophage colony-stimulating factor receptor, alpha subunit on the Y chromosome), ANT3Y (adenine nucleotide translocator-3 on the Y), AZF2 (azoospermia factor 2), BPY2 (basic protein […]

• Y sex-determining region

  A region on the Y chromosome that determines the sex of the individual. This region goes by the symbol SRY (sex region Y). SRY is necessary and sufficient for male sex determination. It is the testis-determining factor. Mutations in SRY give rise to XY females with gonadal dysgenesis who appear to be normal females at […]

• Y map

  The array of genes on the Y chromosome.

• Y chromosome sex-determining region

  The region on the Y chromosome that decides the sex of the individual. Abbreviated SRY. SRY is necessary for male determination. It encodes the testis-determining factor. Mutations in SRY are responsible for XY females with gonadal dysgenesis who appear to be normal females at birth but at puberty do not develop secondary sexual characteristics (such […]

• Y chromosome infertility

  Male infertility with oligozoospermia (a subnormal number of sperm) or azoospermia (the absence of sperm) caused by deletion or rearrangement of the long arm of the Y chromosome, as demonstrated by chromosome analysis or by molecular studies which may show microdeletions (of region AZFa, AZFb, or AZFc) of the Y chromosome. Y chromosome infertility is […]

• Y chromosome

  The sex chromosome that is found, together with an X chromosome, in most normal males. The Y chromosome contains the unique male-determining gene and the male fitness genes that are active only in the testis and are responsible for the formation of sperm. Other genes on the Y chromosome have counterparts on the X chromosome, […]

• X (in genetics)

  Although the letter X can be used as a symbol in various ways (such as with X-rays, the X-axis of a graph, etc.), “the X ” in genetics and medicine today usually refers to the X chromosome. The X is the sex chromosome that is found twice in chromosomally normal females and singly along with […]

• X chromosome

  The sex chromosome that is found twice in normal females and singly, along with a Y chromosome, in normal males. The complete chromosome complement consists of 46 chromosomes, including the 2 sex chromosomes, and is thus conventionally written as 46,XX for chromosomally normal females and 46,XY for chromosomally normal males.

• XYY syndrome

  A chromosomal disorder that affects males only, caused by the presence of an extra Y chromosome. Symptoms may include increased height, speech delays, learning disabilities, mild to moderate mental retardation, and behavioral disturbance. Also known as polysomy Y syndrome.

• Xylitol

  A sweetener that is found in plants and used as a substitute for sugar. Xylitol is called a nutritive sweetener because it provides calories, just like sugar. However, it is less likely than sugar to contribute to dental caries.

• XY

  The most frequent sex chromosome complement in human males.

• XXXXX syndrome

  A chromosome disorder in females, caused by the presence of five X chromosomes rather than the usual two. It is characterized by decreased intelligence (IQ 20 to 75) and multiple malformations including upward-slanting palpebral fissures (eyeslits), heart defect, and small hands with incurving fifth fingers. It is the most severe extra-X syndrome in females. Also […]

• XXXX syndrome

  A chromosome disorder in females caused by the presence of four X chromosomes rather than the usual two. The disorder is characterized by decreased intelligence (IQ 30 to 80; average 55), speech and behavioral problems, tall stature and reduced fertility. Also known as tetra-X syndrome.

• XXX syndrome

  A chromosome condition present in 1 in 1000 females, due to the presence of three X chromosomes rather than the usual two. The condition is associated with increased height but no malformations. Intelligence ranges from above normal to mild retardation. The average IQ is 85 to 90. Learning problems may be helped by early special […]

• XX

  The sex chromosome complement of a normal human female. See also X chromosome.

• Xuezhikang

  One of the three major preparations of red yeast rice, a tradition Chinese medicine now used to lower cholesterol.

• XRT

  Medical abbreviation for radiotherapy.

• Xiphoid process

  The lower part of the breastbone. The xiphoid process has no particular function and ranges in size from miniscule to several inches in length.

• Xerostomia

  Dry mouth. Xerostomia can be associated with systemic diseases, such as Sjogren’s syndrome, systemic lupus erythematosus, and rheumatoid arthritis; and it can be a side effect of medication and poor dental hygiene. Xerostomia results from inadequate function of the salivary glands, such as the parotid glands. Treatment involves adequate intake of water, use of artificial […]

• Xerosis

  Abnormal dryness of the skin, mucous membranes, or conjunctiva (xerophthalmia). There are many causes of xerosis, and treatment depends on the particular cause.

• Xeroradiography

  The process of making a type of dry x-ray in which a picture of the body is recorded on paper rather than on film.

• Xeroradiograph

  A picture of the body recorded on paper rather than on film. Also called a xerogram. From the Greek “xeros” meaning “dry.”

• Xerophthalmia

  Dry eyes. Xerophthalmia can be associated with systemic diseases, such as Sjogren’s syndrome, systemic lupus erythematosus, and rheumatoid arthritis; deficiency of vitamin A; and use of some medications. It results from inadequate function of the lacrimal glands, which produce tears. When xerophthalmia is due to vitamin A deficiency, the condition begins with night blindness and […]

• Xerophagia

  Having a tendency to eat a dry diet.

• Xeromammography

  Xeroradiography of the breast. Xeroradiography is a photoelectric method of recording an x-ray image on a coated metal plate, using low-energy photon beams, long exposure time and dry chemical developers. The prefix xero- comes from the Greek “xeros” meaning “dry.”

• Xerogram

  A picture of the body recorded on paper rather than on film. Also called a xeroradiograph. From the Greek “xeros” meaning “dry.”

• Xeroderma pigmentosum

  A genetic disease that is characterized by such extraordinary sensitivity to sunlight that it results in the development of skin cancer at a very early age. Abbreviated XP. Children with XP can only play outdoors safely after nightfall. XP is due to defective repair of damage done to DNA by ultraviolet (UV) light. Whereas normal […]

• Xeroderma

  Abnormally dry skin. Xeroderma can be caused by a deficiency of vitamin A, systemic illness (such as hypothyroidism or Sjogren’s syndrome), overexposure to sunlight, and medication. Xeroderma can usually be addressed with the use of over-the-counter topical preparations.

• Xero-

  Prefix indicating dryness, as in xeroderma (dry skin).

• Xeric

  Characterized by a scanty supply of moisture (or tolerating or adapted to dry conditions). The word “xeric” is derived from “xeros,” the Greek word for “dry.” “Xeric” was coined in 1926 and was in common scientific usage by the 1940s.

• Xenotropic virus

  A virus that can grow in the cells of a species foreign to the normal host species, a species different from that which normally hosts it. Xeno- means foreign while -tropic refers to growth. So xeno- + -tropic = capable of growing in a foreign environment.

• Xenotransplantation

  Transplantation from one species to another (for example, from a baboon to a human).

• Xenograft

  A surgical graft of tissue from one species to an unlike species (or genus or family). A graft from a baboon to a human is a xenograft. The prefix “xeno-” means foreign. It comes from the Greek word “xenos” meaning stranger, guest, or host. (Xeno- and xen- are variant forms of the same prefix.)

• Xenobiotic

  Natural substances that are foreign to the body.

• Xenoantigen

  An antigen that is found in more than one species. An antigen is something that is capable of inducing an immune response. The prefix “xeno-” means foreign or other. It comes from the Greek “xenos” meaning stranger, guest, or host.

• Xeno- (prefix)

  Xenoantigen — An antigen that is found in more than one species. Xenograft — A surgical graft of tissue from one species an unlike species, genus or family. Xenotransplantation — Transplantation from one species to a foreign one, e.g., the heart transplant from a baboon to Baby Fae in 1984 in Loma Linda, California. Xenotropic […]

• Xanthosis

  Yellowing of the skin without yellowing of the eyes. In jaundice there is yellowing of both the skin and the whites of the eyes. Xanthosis is associated sometimes with malignancies.

• Xanthopsia

  A form of chromatopsia, a visual abnormality in which objects look as though they have been overpainted with an unnatural color. In xanthopsia, that color is yellow.

• Xanthomatosis

  A condition in which fatty deposits occur in various parts of the body. These fatty deposits are called xanthomas or xanthomata and appear as yellowish firm nodules in the skin. Xanthomas are in themselves a harmless growth of tissue. However, they frequently indicate the presence of underlying diseases such as diabetes and disorders of fats […]

• Xanthoma, planar

  A type of xanthoma that is characterized by flat yellow-to-orange patches or pimples that cluster together on the skin.

• Xanthoma, eruptive

  Xanthoma that is linked to lipid disorders and is accompanied by a pink-to-red raised rash.

• Xanthoma, disseminatum

  A type of xanthoma characterized by orange-to-brown nodules on the skin or mucus membranes.

• Xanthoma, diabetic

  Xanthoma that is associated with poorly controlled diabetes mellitus. Treating the diabetes causes diabetic xanthomas to disappear.

• Xanthoma tuberosum

  Xanthoma that clusters near joints and is associated with lipid disorders, cirrhosis of the liver, and thyroid disorders.

• Xanthoma tendinosum

  Xanthoma that clusters around tendons and is associated with lipid disorders, including chronically elevated blood cholesterol levels.

• Xanthoma

  Yellowish firm nodules in the skin frequently indicating underlying disease, such as diabetes, disorder of fats (lipid disorder or hyperlipidemia), or other conditions. A xanthoma is a kind of harmless growth of tissue. Under the microscope, a xanthoma can be seen to be composed of lipid-laden foam cells. These cells, termed histiocytes, contain lipid material […]

• Xanthinuria

  A rare metabolic disorder that is caused by lack of an enzyme needed to process xanthine, an alkaloid found in caffeine; theobromine; theophylline; and related substances. Unchecked, xanthinuria can lead to kidney stone formation. Treatment involves avoiding foods and drinks that contain xanthine derivatives, such as coffee, tea, and cola. Classic xanthinuria is inherited in […]

• Xanthine

  A substance found in caffeine, theobromine, and theophylline and encountered in tea, coffee, and the colas. Chemically, xanthine is a purine. There is a genetic disease of xanthine metabolism, xanthinuria, due to deficiency of an enzyme, xanthine dehydrogenase, needed to process xanthine in the body. Unchecked, xanthinuria can lead to kidney stone formation and urinary […]

• Xanthelasma (Xanthoma) Medical

  Fauci AS, et al. Harrison’s Principles of Internal Medicine. 18th edition. McGraw Hill. 2011

• Xanth- (prefix)

  A condition characterized by yellowish firm nodules in the skin that frequently are a sign of an underlying disease such as diabetes or a disorder of fats (lipid disorder or hyperlipidemia). The word “xanthoma” is made up of “xanth-” from the Greek roots “xanthos” (yellow) and “oma” (swelling) = a yellow swelling. “Xanth” is more […]

• X-rays during pregnancy

  Prenatal radiation exposure.

• X-ray, PA

  An X-ray picture in which the beams pass through the patient posteroanteriorly (from back to front).

• X-ray, lateral

  An X-ray picture that is taken from the side.

• X-ray, AP

  An X-ray picture in which the beams pass through the patient anteroposteriorly (from front to back).

• X-ray crystallography

  The use of X-rays of known wavelength to learn the structure of any crystalline material. Put otherwise, X-ray crystallography is a technology by which the locations of atoms in any crystal can be precisely mapped by looking at the image of the crystal under an X-ray beam. The crystal is placed in the beam of […]

• X-ray

  High-energy radiation with waves shorter than those of visible light. X-ray is used in low doses to make images that help to diagnose diseases and in high doses to treat cancer.

• X-linked

  A gene on the X chromosome that is located on the X chromosome. An X-linked disorder is associated with or caused by a gene on the X chromosome.

• X, factor

  A coagulation factor, a substance in blood essential to the normal clotting process. Production of factor X takes place in the liver and requires vitamin K. The gene for factor X is located on chromosome 13 and is in band 13q34. The “X” in factor X is the Roman numeral “ten.” (All numbered coagulation factors […]

• X inactivation

  it is a heritable change in gene function without a change in the sequence of the DNA. X inactivation is not restricted to females. It also occurs in males with Klinefelter syndrome who have more than one X chromosome. The phenomenon of X inactivation is also called lyonization after the English geneticist Mary Lyon (1925-) […]

• Waardenburg syndrome

  A genetic disorder that causes deafness, white forelock (a frontal white blaze of hair), a difference of color between the iris of one eye and the other (heterochromia iridis), white eye lashes, and wide-set inner corners of the eyes. The deafness is typically congenital (present at birth), bilateral, profound sensorineural (nerve) deafness. The severity of […]

• Waardenburg, Petrus Johannes

  (1886-1979) Dutch ophthalmologist and medical geneticist who described the condition now known as Waardenburg syndrome. The syndrome is characterized by wide bridge of the nose owing to lateral displacement of the inner canthus of each eye, pigmentary disturbance (frontal white blaze of hair, eyes of different color, white eye lashes, leukoderma), and cochlear deafness. Waardenburg […]

• Wagner syndrome

  a genetic condition caused by a mutation in the gene (CSPG2 on chromosome 5) encoding chondroitin sulfate proteoglycan-2, also known as versican. Versican is a substance present in the vitreous body of the eye. Symptoms and signs include changes in the vitreous body of the eye, retinal detachment, cataracts, and poor visual adaptation to dark. […]

• Wymmin

  An alternate spelling of wimmin.

• Wymin

  An alternate spelling of wimmin.

• Wt

  Abbreviation for weight. For example, ‘Wt 80 lbs’ means ‘weight 80 pounds.’

• Wry neck

  Medically called spasmodic torticollis, or torticollis. The most common of the focal dystonias. In torticollis, the muscles in the neck that control the position of the head are affected, causing the head to twist and turn to one side. In addition, the head may be pulled forward or backward.

• Writer’s cramp

  A dystonia that affects the muscles of the hand and sometimes the forearm and that only occurs during handwriting. Similar focal dystonias have been called typist’s cramp, pianist’s cramp, musician’s cramp, and golfer’s cramp.

• Writer’s cramp

  A dystonia that affects the muscles of the hand and sometimes the forearm and only occurs during handwriting. Similar focal dystonias have also been called typist’s cramp, pianist’s cramp, musician’s cramp, and golfer’s cramp.

• Wrist

  The part of the hand that is nearest the forearm and consists of the carpal bones and the associated soft tissues. The eight carpal bones are arranged in two rows. One row of carpal bones joins the long bones of the forearm (the radius, and, indirectly, the ulna). Another row of carpal bones meets the […]

• WPW syndrome

  Wolff-Parkinson-White syndrome.

• Wormwood

  The essence of absinthe, an emerald-green spirit, flavored with extracts of the wormwood plant, licorice and aromatic flavorings in a alcohol base. Absinthe was manufactured, commercialized and popularized in France in the late 1700s by Henri-Louis Pernod. It became an extremely popular drink. Among the famous figures who made absinthe a symbol of decadence were […]

• World Health Organization

  The subagency of the United Nations (UN) that is concerned with international health. Abbreviated WHO. Also known as Organisation Mondiale de la Sant’ (OMS).

• Working memory

  Short-term (recent) memory. Working memory is a system for temporarily storing and managing the information required to carry out complex cognitive tasks such as learning, reasoning, and comprehension. Working memory is involved in the selection, initiation, and termination of information-processing functions such as encoding, storing, and retrieving data. One test of working memory is memory […]

• Wordprocessor’s cramp

  A form of focal dystonia caused by wordprocessing that affects the muscles of the hand and, sometimes, the forearm. The term “dystonia” refers to a state of abnormal (too much or too little) muscle tone. There are many forms of dystonia. Dystonia disorders cause involuntary movements and prolonged muscle contraction, resulting in twisting body motions, […]

• Word blindness

  A neurological disorder characterized by loss of the ability to read or understand the written word. Word blindness is a complex visual disturbance resulting from disease in the visual-association areas at the back of the brain. Someone who has had a stroke may be left with pure (total) or partial word blindness. Partial word blindness […]

• Womyn

  Woman. A late 20th century feminist creation to avoid the suffix man.

• Women’s hospital

  A hospital for the exclusive use of women. The first hospital called by that name was the Woman’s Hospital of New York City. It opened in 1855. The hospital was founded by the Woman’s Hospital Assn., a group of 30 women who held that there women needed a hospital to care exclusively for them. In […]

• Women’s Health Initiative

  This component starts up to 2 years after a woman joins one or both of the other studies. It evaluates the effect of calcium and vitamin D supplementation on the prevention of osteoporosis-related fractures and colorectal cancer. Women in this component take calcium and vitamin D pills or a placebo. The WHI Community Prevention Study […]

• Womb

  The womb (uterus) is a hollow, pear-shaped organ located in a woman’s lower abdomen between the bladder and the rectum. The narrow, lower portion of the uterus is the cervix; the broader, upper part is the corpus. The corpus is made up of two layers of tissue. In women of childbearing age, the inner layer […]

• Wolhynia fever

  184-189, 1999). The organism (B. quintana) that causes trench fever also has been found responsible for a disease called bacillary angiomatosis in people infected with HIV and for infection of the heart and great vessels (endocarditis) with bloodstream infection. Trench fever is also called shin bone fever, quintan fever, five-day fever, Meuse fever, His’ disease, […]

• Wolfram syndrome

  A genetic neurodegenerative disease that leads to many different abnormalities including diabetes insipidus (inability to concentrate the urine), diabetes mellitus (the usual type of diabetes), blindness (due to optic atrophy, degeneration of the nerve to the eye), and deafness. Patients usually also suffer from severe abnormalities of the nervous system that can be accompanied by […]

• Wolff-Parkinson-White syndrome

  A condition that is caused by an abnormality in the electrical system of the heart, which normally tells the heart muscle when to contract. Abbreviated WPW syndrome. In WPW syndrome there is an extra electrical connection inside the heart that acts as a short circuit, causing the heart to beat too rapidly and sometimes in […]

• Wolf-Hirschhorn syndrome

  Abbreviated WHS. A chromosome disorder due to partial deletion of the short (p) arm of chromosome 4. It is therefore also called the 4p- syndrome. Features of the syndrome include midline defects with a scalp defect, widespaced eyes, broad or beaked nose, oral facial clefts (cleft lip/palate); low simple ears with a dimple in front […]

• WNL

  Medical shorthand for within normal limits. For example, a laboratory test result may be WNL.

• WM

  Medical shorthand for white male.

• Witkop syndrome

  A genetic disorder characterized by the absence of several teeth at birth and abnormalities of the nails. The disorder is also known as hypodontia and nail dysgenesis or, more picturesquely, as the tooth and nail syndrome (TNS). The tooth and nail defects in the syndrome are highly variable. The number and type of congenitally missing […]

• Withdrawal, penis

  A method of contraception, also called coitus interruptus, in which the man withdraws his penis from the vagina before ejaculation. Fertilization is prevented because the sperm do not enter the vagina. The effectiveness of this maneuver depends on the man’s ability to withdraw before the ejaculation of any sperm. Withdrawal does not provide protection from […]

• Withdrawal symptoms

  Abnormal physical or psychological features that follow the abrupt discontinuation of a drug that has the capability of producing physical dependence. In example, common opiates withdrawal symptoms include sweating, goosebumps, vomiting, anxiety, insomnia, and muscle pain.

• Witch’s milk

  A folk term for the milk that often comes from the breast of a newborn baby. This temporary phenomenon is due to stimulation of the baby’s breasts by the mother’s hormones that cross the placenta during pregnancy. The ability of the baby’s breasts to respond in this fashion is a mark of baby born at […]

• Wisdom tooth

  One of the large molars in the very back of the jaw. The human jaw has changed in size over the course of evolution, and wisdom teeth are no longer needed, but they continue to erupt in many individuals. If the jaw is too small to accommodate them, they may cause pain or crowd other […]

• Wing bone

  Popular and familiar term for the scapula, the flat triangular bone at the back of the shoulder. The word “scapula” (with the accent on the first syllable) is a steal straight from the Latin. The Romans always employed the plural “scapulae”, the shoulder blades. Because the shoulder blade resembles the blade of a trowel (a […]

• Windpipe

  The trachea, a tube-like portion of the respiratory (breathing) tract that connects the larynx (the voice box) with the lungs. Each time we inhale (breathe in), air goes into our nose or mouth, then through the larynx, down the trachea, and into our lungs. When we exhale (breathe out), the air goes out the other […]

• Wimmin

  Women. A late 20th century creation. A feminist spelling to avoid the suffix men.

• Wilson disease

  An inherited disorder of copper metabolism that results in an abnormal accumulation of copper in the body. Although the accumulation of copper begins at birth, symptoms of the disorder do not appear until later in life, between the ages of 6 and 40. A diagnostic feature of the disease is a Kayser-Fleischer ring, a deep […]

• Wilms tumor

  A childhood form of kidney cancer with a peak age of occurrence at 3 years of age. It is sometimes associated with abnormalities of the urinary tracts or other birth defects. Some cases are related to defects in one of two genes referred to as Wilms’ tumor 1 (WT1) or Wilms’ tumor 2 (WT2). Symptoms […]

• Willis, circle of

  A critical arterial circle at the base of the brain. The circle of Willis receives all the blood that is pumped up the two internal carotid arteries that come up the front of the neck. All the principal arteries that supply the two halves of the brain (hemispheres) branch off from the circle of Willis.

• Williams syndrome

  A genetic disorder characterized by mild mental retardation, unique personality characteristics, unusual facial features, and cardiovascular disease. The level of calcium tends to be high in blood (hypercalcemia) and urine (hypercalciuria). Mental retardation is the rule and ranges from severe to mild. Personality features include overfriendliness, general anxiety, and attention deficit disorder. Facial features include […]

• Will, living

  An advance medical directive that specifies what types of medical treatment are desired. A living will can be very specific or very general. The most common statement in a living will requests that if the patient suffers an incurable, irreversible illness

• Wilkins, Lawson

  American physician (1894-1963) who founded pediatric endocrinology. At Johns Hopkins Medical School in Baltimore, Dr Wilkins started a clinic devoted to pediatric endocrinology and focused particularly on problems of growth and genetics.

• Wildervanck syndrome

  A syndrome characterized by the combination of congenital deafness, Duane syndrome (eye retraction), and fusion of the neck vertebrae (Klippel-Feil anomaly). Wildervanck syndrome is limited, or almost completely limited, to females. The syndrome is probably due to polygenic inheritance with limitation to females and lethality for males.

• Wiedemann-Beckwith syndrome

  Beckwith-Wiedemann syndrome.

• Whooping cough

  Whooping cough, also known as “pertussis,” is a highly contagious, acute respiratory illness characterized by fits of coughing and caused by the bacteria Bordetella pertussis. Whooping cough, a communicable, potentially deadly illness characterized by fits of coughing followed by a noisy, “whooping” indrawn breath. It is caused by the bacteria Bordetella pertussis. The illness is […]

• Whole-arm translocation

  A type of chromosome rearrangement, also called a Robertsonian translocation, in which there is fusion of an entire long arm of one acrocentric chromosome with a similarly intact long arm of another acrocentric chromosome. The short arms of the chromosomes participating in the translocation are usually lost. Acrocentric chromosomes have their centromere near but not […]

• World Health Organization

  The subagency of the United Nations (UN) that is concerned with international health. Abbreviated WHO. Also known as Organisation Mondiale de la Sant’ (OMS).

• Whitmore-Jewett staging system

  A staging system for prostate cancer. See Jewett staging system.

• Whitmore’s disease

  Surgical removal of the lung abscess with lobectomy is considered. Antibiotic treatments may be necessary from 3 to 12 months. Melioidosis can remain latent (in hiding) for years and emerge when a person’s resistance is low. The alternative name for melioidosis is, as mentioned, Whitmore’s disease. This is in honor of Major Alfred Whitmore (1876-1946), […]

• Whitehead

  A familiar term for what is medically called a closed comedo. A comedo, the primary sign of acne, consists of a dilated (widened) hair follicle filled with keratin squamae (skin debris), bacteria, and sebum (oil). A whitehead is a comedo that has an obstructed opening to the skin. A closed comedo may rupture and cause […]

• White coat hypertension

  A transient increase in blood pressure (hypertension) that is triggered by the sight of medical personnel in white coats (or other attire). Ideally, people so affected should do their best to relax when in the medical office.

• White subungual onychomycosis, proximal

  The rarest form of fungus infection of the finger or toenail. (Fungus infection of the finger or toenail is also called onychomycosis.) The infection begins in the nail fold (the portion of the nail opposite the tip of the finger). Proximal white subungual onychomycosis is typically associated with HIV infection (AIDS), though it can follow […]

• White spots on the nails

  Very small semi-circular white spots on the nails. These spots may be found on the fingernails and, particularly, the toenails. The white spots on the nails reflect injury to the base (matrix) of the nail. The matrix is the part under the visible nail where the nail cells and the nail itself are produced. The […]

• White phosphorus

  A waxy solid which burns easily and is used in chemical manufacturing and smoke munitions. It is also used by industry to produce phosphoric acid and other chemicals for use in fertilizers, food additives, and cleaning compounds. Small amounts of white phosphorus were used in the past in pesticides and fireworks. Breathing white phosphorus for […]

• White matter

  The part of the brain that contains myelinated nerve fibers. The white matter is white because it is the color of myelin, the insulation that covers nerve fibers.

• White coat hypertension

  A transient increase in blood pressure (hypertension) that is triggered by the sight of medical personnel in white coats (or other attire). Ideally, people so affected should do their best to relax when in the medical office.

• White cell differential, automated

  A machine-generated percentage of the different types of white blood cells, usually split into granulocytes, lymphocytes, monocytes, eosinophils, and basophils.

• White blood cell count

  The number of white blood cells (WBCs) in the blood. The WBC is usually measured as part of the CBC (complete blood count). White blood cells are the infection-fighting cells in the blood and are distinct from the red (oxygen-carrying) blood cells known as erythrocytes. There are different types of white blood cells, including neutrophils […]

• White blood cell

  One of the cells the body makes to help fight infections. There are several types of white blood cells (leukocytes). The two most common types are the lymphocytes and neutrophils (also called polymorphonuclear leukocytes, PMNs, or “polys”). Lymphocytes are made in lymphoid tissue in the spleen, lymph nodes, and thymus gland. There are different kinds […]

• Whipworm

  A nematode (roundworm), also called Trichuris trichiura, that is the third most common roundworm in humans. The whipworm is found worldwide, and whipworm infections are most frequent among children and in areas with tropical weather and poor sanitation practices. Infection with whipworm most often occurs without symptoms. Heavy infections, especially in small children, can cause […]

• Whipple procedure

  A type of surgery that is used to treat pancreatic cancer and was devised by the US surgeon Allen Whipple. The head of the pancreas, the duodenum, a portion of the stomach, and other nearby tissues are removed.

• Whipple disease

  A form of inability to absorb nutrients from the intestine. It can affect any part of the body, leading to arthritis and then weight loss, cough, fever, diarrhea, hypotension (low blood pressure), abdominal swelling, increased skin pigmentation, and severe anemia. Whipple disease has been discovered to be due to a type of bacteria named Tropheryma […]

• Whiplash injury

  The victim may be first pushed or accelerated forward, pushing the body forward, but the head remains behind momentarily, rocking up and back, and some muscles and ligaments in and around the spine may be stretched or torn. These muscles, in a reflex action, contract to bring the head forward again, to prevent excessive injury. […]

• WHI

  The Women’s Health Initiative, a long-term health study sponsored by the National Institutes of Health (NIH) focused on strategies for preventing heart disease, breast cancer, colorectal cancer and osteoporosis in postmenopausal women.

• Wheezing

  A whistling noise in the chest during breathing. Wheezing occurs when the airways are narrowed or compressed.

• Wheezer

  A slang term for a patient who is wheezing. Sometimes applied to someone having serious trouble breathing.

• Wheal

  A raised, itchy (pruritic) area of skin that is sometimes an overt sign of allergy. Not all wheals are alike. They may be redder or paler than the skin around them. They may vary in configuration and may be rounded or flat-topped. Wheals typically have a reddish hue. They characteristically change in size and shape […]

• Wharton’s jelly

  A gelatinous substance that provides insulation and protection within the umbilical cord. Stem cells are present in Wharton’s jelly, as well as in umbilical cord blood.

• WFS1

  A gene on the short (p) arm of chromosome 4 in band 4p16 that encodes (provides the instructions for) a protein called wolframin. Mutations in WFS1 are associated with Wolfram syndrome and with nonsyndromic deafness (hearing loss without related signs and symptoms affecting other parts of the body). Wolframin is found in cells throughout the […]

• WF

  Medical shorthand for white female.

• Wet market

  A live animal market, a common sight in many areas of the world and a source of influenza viruses and other infectious disease agents for human beings. SARS outbreaks have been traced to wet markets in southern China. Wet markets sell live poultry, fish, reptiles, and mammals of every kind. Animals may stay from days […]

• Western medicine

  Conventional medicine, as distinct from an alternative form of medicine such as ayurvedic or traditional Chinese medicine.

• Western blot

  A technique in molecular biology that is used to separate and identify particular proteins.

• West syndrome

  Infantile spasms, a seizure disorder of infancy and early childhood with the onset predominantly in the first year of life of myoclonic seizures, hypsarrhythmia (abnormal, chaotic electroencephalogram), and mental retardation. The spasms are sudden, brief contractions of one or more muscle groups, and may be followed by a longer (less than 10 seconds) tonic phase. […]

• West Nile virus

  The mosquito-borne virus that causes West Nile fever. One of the flaviviruses, a family of viruses also responsible for dengue, yellow fever, and tick-borne encephalitis virus. Like the other flaviviruses, the West Nile virus is a positive-strand RNA virus containing three structural proteins and a host-derived lipid bilayer. The West Nile virus is an icosahedral […]

• West Nile fever

  A febrile disease caused by the West Nile virus that is transmitted from birds to the common Culex mosquito and then to people. The virus is named after the area it was first found in Uganda. West Nile fever occurs in parts of Africa and Asia and, infrequently, in Southern Europe and the Middle East. […]

• Werner-His disease

  184-189, 1999). The organism (B. quintana) that causes trench fever also has been found responsible for a disease called bacillary angiomatosis in people infected with HIV and for infection of the heart and great vessels (endocarditis) with bloodstream infection. Trench fever is also called Wolhynia fever, shin bone fever, quintan fever, five-day fever, Meuse fever, […]

• Werner syndrome

  A premature aging disease that begins in adolescence or early adulthood and results in apparent old age by 30’40 years of age. Characteristic features include short stature, premature graying, early baldness, wizened face, beaked nose, cataracts, skin changes reminiscent of those in scleroderma, deposits of calcium beneath the skin, premature arteriosclerosis, and a tendency to […]

• Werdnig-Hoffman Disease (SMA-1) Medical Definition

  //emedicine.medscape.com/article/1181436-overview>.

• Welt

  in sewing, an edge of cloth folded on itself, often over a cord, and sewed down; and in shoemaking, a narrow strip of leather around the shoe between the upper leather and sole.

• Weight Watchers

  The core plan is based on the consumption of wholesome foods from all the food groups, including fruits and vegetables, grains and starches, lean meats and poultry, and eggs and dairy products.

• Weight loss

  Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight […]

• Wegener’s granulomatosis

  An uncommon type of inflammation of small arteries and veins (vasculitis) that classically involves the vessels supplying the tissues of the lungs, nasal passages (sinuses), and kidneys. Wegener’s granulomatosis usually affects young or middle-aged adults. Symptoms include fatigue, weight loss, fever, shortness of breath, bloody sputum, joint pains, and sinus inflammation, sometimes with nasal ulcerations […]

• Weaver’s bottom

  Inflammation of the bursa that separates the gluteus maximus muscle of the buttocks from the underlying bony prominence of the bone that a person sits on (ischial tuberosity). Weaver’s bottom is a form of bursitis that is usually caused by prolonged sitting on hard surfaces that press against the bones of the bottom or midbuttocks. […]

• Weaver syndrome

  An overgrowth syndrome characterized by accelerated growth and advanced bone age (evident at birth), unusual craniofacial appearance, hoarse low-pitched cry, and hypertonia (increased muscle tone) with camptodactyly (inability to fully extend the fingers). Caused by mutations in a gene called NSD1. The same gene is mutated in more than three-fourths of patients with another overgrowth […]

• Weasand

  1. The windpipe (trachea). 2. More loosely, the throat. “Cut his weasand with thy knife.” The Tempest, Shakespeare. Weasand is from the Middle English wesand and the Old High German weisunt meaning windpipe. Sometimes written wesand or wezand.

• WDWN

  Abbreviation for ‘well-developed, well-nourished,’ shorthand used by physicians when jotting down the results of a physical examination. For example, a WDWNWF would be a well-developed, well-nourished white female.

• WBS

  Beckwith-Wiedemann syndrome.

• Wax, ear

  wet and dry. Most whites and blacks have the wet type, and most Asians and Native Americans have the dry type.

• Wax dip

  A treatment for the symptoms of joint and muscle conditions, such as arthritis, that consists of melted mineral wax derived from petroleum applied to a body area. Wax dips can be especially helpful in relieving the pain and stiffness of arthritis involving the small joints of the hands when used as a small bath. The […]

• Watson, James

  “Your discovery of the molecular structure of the deoxyribonucleic acid, the substance carrying the heredity, is of utmost importance for our understanding of one of the most vital biological processes. Practically all the scientific disciplines in the life sciences have felt the great impact of your discovery. The formulation of double helical structure of the […]

• Watermelon stomach

  Parallel red sores in the stomach that look like the stripes on a watermelon. Frequently seen with cirrhosis of the liver.

• Watermelon

  A fruit of African origin that is, in reality, a vegetable related to cucumbers and squash. Watermelon is 92% water and 8% sugar. It is rich in lypocene, an antioxidant that gives it its characteristic color. It is fat free.

• Waterborne bacterial disease

  Vibrio cholerae, Campylobacter, Salmonella, Shigella and Escherichia coli (E. coli). Waterborne bacterial infections account for 2-3 billion episodes of diarrhea resulting in 1-2 million deaths a year. The deaths tend to be of infants and young children from dehydration, malnutrition, and other complications of waterborne bacterial infections. At high risk are the two billion people […]

• Water retention

  A nonspecific term meaning the accumulation of excess fluids in body tissues, medically known as edema. Edema can result from many different disease processes, including but not limited to diseases of the heart and circulation and kidney disease. Water retention is also used to describe the symptoms of feeling bloated or experiencing a small weight […]

• Water requirements, infant

  failing to adequately dilute the concentrates with water causes the formulas to be too “hypertonic.” Hypertonic formulas can induce diarrhea and dehydration. In extreme cases, ingestion of overly hypertonic formulas can lead to kidney failure, gangrene of the legs, and coma. Therefore, parents should not adjust the amount of water that is added to concentrates […]

• Water on the brain

  In infants the most obvious sign of hydrocephalus is usually an abnormally large head. (That is one reason a baby’s head should be measured at every well-baby visit). Symptoms of hydrocephalus in an infant may include vomiting, sleepiness, irritability, an inability to look upwards, and seizures. In older children and adults there is no head […]

• Water intoxication

  A lowered blood concentration of sodium (see hyponatremia). The term “water intoxication” is generally used to refer to hyponatremia that occurs due to the consumption of excess water without adequate replacement of sodium, as may happen during strenuous exercise.

• Water blister

  A blister with clear watery contents that is not purulent (does not contain pus) and is not sanguineous (does not contain blood). A blister is medically termed a vesicle. One that is more than 5 mm in diameter with thin walls and is full of watery fluid is called a bulla. The word “blister” entered […]

• Water

  1. A tasteless odorless colorless liquid with the chemical formula H2O. 2. The liquid which forms rain, rivers, and the sea and makes up a large part of the bodies of most organisms, including humans. 3. The amniotic fluid, as in the bag of waters. 4. The cerebrospinal fluid, especially under increased pressure, as in […]

• Watchful waiting

  Closely monitoring a patient’s condition but withholding therapy until the sign and symptom appear or change. Also called observation.

• Wasting

  1. Gradual loss (for example, of weight), deterioration, emaciation. As in a wasting disease. 2. Excessive depletion. As in salt wasting, the excessive loss of salt.

• Wasp sting

  A sting from a wasp, which can trigger allergic reactions that vary greatly in severity. Avoidance and prompt treatment are essential. In some cases, allergy injection therapy is highly effective.

• Warts, plantar

  Warts that grow on the soles of the feet. Plantar warts are different from most other warts. They tend to be flat and cause the buildup of the top layer of the skin (that has to be peeled away before the plantar wart itself can be seen. They can be quite painful. Plantar warts are […]

• Wart, genital

  A wart that is confined primarily to the moist skin of the genitals. These warts are due to viruses belonging to the family of human papilloma viruses (HPVs) which are transmitted through sexual contact. The virus can also be transmitted from mother to baby during childbirth. Most people infected with HPV have no symptoms but […]

• Wart

  A local growth of the outer layer of the skin (the epidermis) caused by a virus. The virus of warts (a papillomavirus) is transmitted by contact. The contact can be with a wart on someone else or one on oneself (autoinoculation). Warts that occur on the hands or top of the feet are called “common […]

• Warshaw, Joseph

  (1936-2003) Eminent American pediatrician and pioneer in human developmental biology. Warshaw used biochemical, cell biological and molecular techniques to investigate the regulation of fetal growth and perinatal adaptation. Dr. Warshaw began working in the area of developmental metabolism while at Harvard Medical School and Massachusetts General Hospital from 1967 to 1973. He moved to Yale […]

• Warfarin, teratogenicity of

  The anticoagulant warfarin (COUMADIN) is a known teratogen, an agent that can disturb the development of the embryo and fetus and lead to birth defects.. Warfarin taken by a woman during pregnancy can cause bleeding into the baby’s brain (cerebral hemorrhage), underdevelopment (hypoplasia) of the baby’s nose and stippling of the ends (the epiphyses) of […]

• Warfarin

  Coumarin, Panwarfin, Sofarin) taken to prevent the blood from clotting and to treat blood clots and overly thick blood. Warfarin is also used to reduce the risk of clots causing strokes or heart attacks. Warfarin works by suppressing the production of some clotting factors (interfering with prothrombin activation) and thereby inhibiting the clotting of blood. […]

• Warburg’s yellow enzyme

  A key respiratory enzyme discovered by the German biochemist Otto Heinrich Warburg (1883-1970), a pioneer in research on the respiration of cells and the metabolism of tumors. Warburg’s yellow enzyme is a flavoprotein that catalyzes an oxidation-reduction reaction. This reaction is necessary for the cells to normally breathe (respire), or use oxygen. Warburg won the […]

• Warburg apparatus

  A device used in biochemistry for measuring breathing (respiration) by tissues. Tissue slices are enclosed in a chamber in which the temperature and pressure are monitored, and the amount of gas produced or consumed by the tissue is measured. The Warburg apparatus was invented by the German biochemist Otto Heinrich Warburg (1883-1970), a pioneer in […]

• Warble

  A small hard nodule produced by the larva of a fly that has penetrated the skin. The warble can be erythematous (reddened). The most common complication is a secondary bacterial infection around the warble. The usual treatment is to extract the larva by gentle pressure and forceps.

• Wamble

  1. To move unsteadily; an unsteady motion. 2. To feel nauseated; a feeling of nausea. 3. (Of a stomach) To rumble or growl. From the Middle English wamelen (to feel nausea), from the Indo-European root wem- (to vomit), the source of the words such as vomit and emetic.

• Walleyed

  1. Having exotropia — divergent strabismus — in which the eyes turn outward away from the nose. The Japanese term is ron-pari, as one eye is looking at Rondon (London) and the other is looking at Pari (Paris). 2. Having a dense white opacity (leukoma) of the cornea. 3. Having large staring eyes, like those […]

• Walking pneumonia

  PubMed Health.com. Atypcial Pneumonia.

• Waldenstrom macroglobulinemia

  A chronic low-grade (indolent) type of lymphoma due to a malignant clone of plasma cells. These plasma cells multiply out of control, invade the bone marrow, lymph nodes, and spleen, and characteristically produce huge amounts of a large-sized antibody called macroglobulin or IgM. The excess IgM causes the blood to be hyperviscous (to thicken). Waldenstrom […]

• VHL

  Von Hippel-Lindau. See Von Hippel-Lindau syndrome.

• Viable

  Capable of life. For example, a viable premature baby is one who is able to survive outside the womb.

• Vibramycin

  Brand name for doxycycline.

• VWM

  Leukoencephalopathy with vanishing white matter, an inherited brain disease that occurs mainly in children. and follows a chronic progressive course with additional episodes of rapid deterioration following stress from febrile infection or minor head trauma. VWM is due to mutations in either of two genes — in either the EIF2B5 gene on chromosome 3q27 or […]

• Vulvodynia, essential

  A chronic, diffuse, unremitting sensation of burning of the vulva — (the female external genital organs including the labia, clitoris, and entrance to the vagina)– a painful sensation which may extend to the perineum, thigh or buttock and is often associated with discomfort in the urethra and rectum. Vulvodynia means “painful vulva.” Essential vulvodynia occurs […]

• Vulvitis, yeast

  A yeast infection of the external genital organs of the female (the vulva). The vulva includes the labia, clitoris, and the entrance (the “vestibule”) to the vagina. Yeast vulvitis commonly goes together with yeast vaginitis, infection of the vagina by the fungus known as Candida. The common symptoms are itching, burning, soreness, pain during intercourse […]

• Vulvitis

  Inflammation of the external genital organs of the female (the vulva). The vulva includes the labia, clitoris, and the entrance (the “vestibule”) to the vagina. A yeast infection of the vulva, for example, is a type of vulvitis.

• Vulvar vestibulitis

  Inflammation of small glands at the entrance to the vagina. Vulvar vestibulitis is the most common physical cause of painful intercourse in young women. In roughly half of cases, the condition appears due to a rare form of a gene (the interleukin-1 receptor antagonist gene) that regulates inflammation.

• Vulvar pain, chronic

  Also called essential vulvodynia (literally means “painful vulva”), pain in the vulva, the female external genitalia including the labia, clitoris, and entrance to the vagina. The pain usually is a chronic, diffuse, unremitting sensation of burning which may extend to the perineum, thigh or buttock and is often associated with discomfort in the urethra and […]

• Vulvar

  Pertaining to the vulva, the female external genitalia including the labia majora, labia minora, clitoris, the tiny glands called Bartolin’s glands, and the entrance to the vagina (the vestibule of the vagina).

• Vulva

  The female external genital organs, including the labia, clitoris, and entrance to the vagina.

• Vulnerary

  (Plural = vulneraries). A remedy used in healing or treating wounds. Any preparation, plant or drug used in the cure of wounds. For example, Native Americans used the herb echinacea as a vulnerary for burns, snakebites, arrow and other wounds. It was considered something of a panacea. “Vulnerary” comes from the Latin “vulnus” meaning “wound.” […]

• Vrolik’s disease

  Osteogenesis imperfecta type II, an inherited connective tissue disorder with very severe bone fragility, the lethal form of “brittle bone disease.” It is a recessive trait with males and females affected. Two copies of the mutant gene are needed to cause the disease. Clinically the disease is characterized by short limb dwarfism, thin skin, soft […]

• Voyeurism

  Voyeurism is a disorder that involves achieving sexual arousal by observing an unsuspecting and non-consenting person who is undressing or unclothed, and/or engaged in sexual activity. This behavior may conclude with masturbation by the voyeur. The voyeur does not seek sexual contact with the person he is observing. Other names for this behavior are “peeping” […]

• Von Willebrand disease

  The most common inherited bleeding disorder, in which a clotting protein called von Willebrand factor is deficient or defective. Von Willebrand factor is made by cells lining the wall of blood vessels. Several types of von Willebrand disease have been described. All types affect both males and females. Symptoms can include easy bruising, nosebleeds, bleeding […]

• von Recklinghausen disease

  Neurofibromatosis type 1. A genetic disease characterized by the formation of neurofibromas.

• Von Hippel-Lindau syndrome

  A genetic disease that is characterized by hemangioblastomas (benign blood vessel tumors) in the brain, spinal cord, and retina; kidney cysts, and kidney cancer (renal cell carcinoma); pheochromocytomas (benign tumors of adrenal-like tissue); and endolymphatic sac tumors (benign tumors of the labyrinth in the inner ear). Abbreviated VHL syndrome. The brain hemangioblastomas in VHL syndrome […]

• Vomitus

  Matter from the stomach that has come up into and may be ejected beyond the mouth, due to the act of vomiting. When vomitus is reddish or the color of coffee grounds, it may mean there is serious internal bleeding. The reddish color may herald fresh blood and dark blood may betoken blood that has […]

• Vomiting of pregnancy, pernicious

  Medically known as hyperemesis gravidarum, this is excessive vomiting in early pregnancy. By definition, hyperemesis gravidarum, leads to the loss of 5% or more of the body weight of the woman. Hyperemesis gravidarum affects about one in every 300 pregnant women. It is more common in young women, in first pregnancies and in women with […]

• Vomiting in pregnancy, excess

  Medically known as hyperemesis gravidarum, this is excessive vomiting in early pregnancy. By definition, hyperemesis gravidarum, leads to the loss of 5% or more of the body weight of the woman. Hyperemesis gravidarum affects about one in every 300 pregnant women. It is more common in young women, in first pregnancies and in women with […]

• Vomit

  Matter from the stomach that has come up into and may be ejected beyond the mouth, due to the act of vomiting. When vomit is reddish or the color of coffee grounds, it may mean there is serious internal bleeding. The reddish color may herald fresh blood and dark blood may betoken blood that has […]

• Vomer

  A triangular bone in the nasal septum. The bone was so named because it was thought to look like a ploughshare, the part of the plow that cuts the furrow. Vomer is the Latin word for ploughshare.

• Volvulus

  Abnormal twisting of a portion of the gastrointestinal tract, usually the intestine, which can impair blood flow. Volvulus can lead to gangrene and death of the involved segment of the gastrointestinal tract, intestinal obstruction, perforation of the intestine, and peritonitis. The stomach, small intestine, cecum, and sigmoid colon are all subject to volvulus. Malrotation of […]

• Voluntary Euthanasia Society (VES)

  The first society of its kind in the world — its founders included doctors, lawyers and churchmen — the VES was set up in England in 1935. The announced aim of the VES is to make it legal for a competent adult suffering unbearably from an incurable illness to receive medical help to die at […]

• Voluntary

  Done in accordance with the conscious will of the individual. The opposite of involuntary. The terms “voluntary” and “involuntary” apply to the human nervous system and its control over muscles. The nervous system is divided into two parts — somatic and autonomic. The somatic nervous system operates muscles that are under voluntary control. The autonomic […]

• Volume, stroke

  The amount of blood pumped by the left ventricle of the heart in one contraction. The stroke volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat. Together with the heart rate, the stroke volume determines the output of […]

• Volar

  Pertaining to the palm or the sole. For example, the volar surface of the forearm is the portion of the forearm that is on the same side as the palm of the hand.

• Voiding cystourethrography

  A procedure done to examine the bladder and urethra while the bladder fills and empties. A radiopaque liquid (that can be seen on x-ray) is placed in the bladder through a catheter. The bladder is filled until the patient urinates. Radiographs (x-rays) are usually taken before, during, and after voiding. This test can reveal abnormalities […]

• Voiding cystourethrogram

  A test done to examine the bladder and urethra while the bladder fills and empties. A radiopaque liquid (that can be seen on x-ray) is placed in the bladder through a catheter. The bladder is filled until the patient urinates. Radiographs (x-rays) are usually taken before, during, and after voiding. This test can reveal abnormalities […]

• Void

  To urinate. The term void is also sometimes used to indicate the elimination of solid waste (defecation).

• Voice disorder

  Voice disorder is characterized by the abnormal production and/or absences of vocal quality, pitch, loudness, resonance, and/or duration, which is inappropriate for an individual’s age and/or sex.

• Voice box

  The voice box, or larynx, is the portion of the respiratory (breathing) tract containing the vocal cords which produce sound. It is located between the pharynx and the trachea. The larynx, also called the voice box, is a 2-inch-long, tube-shaped organ in the neck. We use the larynx when we breathe, talk, or swallow. Its […]

• Vohwinkel syndrome

  A genetic disorder characterized by hearing loss and thickened skin, particularly on the knuckles. The sensorineural hearing is mild-to-moderate in degree. The thickening of the skin (hyperkeratosis) can be “mutilating” and cause autoamputation of the digits. The syndrome is inherited in an autosomal dominant manner. It is caused by mutation in the GJB2 gene (connexin […]

• Vocal cord paralysis

  Inability of one or both vocal folds (vocal cords) to move. The paralysis is usually due to damage to the nerves going to the vocal cords or due to damage to the brain itself. In more technical terms, vocal cord paralysis may result from lesions in the nucleus ambiguus or its supranuclear tracts in the […]

• Vocal cord

  We use the larynx when we breathe, talk, or swallow. Its outer wall of cartilage forms the area of the front of the neck referred to as the “Adams apple.” Each time we inhale (breathe in), air goes into our nose or mouth, then through the larynx, down the trachea, and into our lungs. When […]

• Vitreous

  A clear, jelly-like substance that fills the middle of the eye. Also called the vitreous humor, “humor” in medicine referring to a fluid (or semifluid) substance.

• Vitrectomy

  Removal of the gel (called the vitreous) from within the eyeball. This may be done because it has blood and scar tissue in it that blocks sight. The eye surgeon then replaces the clouded gel with a clear fluid.

• Vitiligo

  A condition in which the skin turns white due to the loss of pigment from the melanocytes, cells that produce the pigment melanin that gives the skin color. In vitiligo, the melanocytes are destroyed, leaving depigmented patches of skin. The hair that grows in areas affected by vitiligo may also turn white. The skin is […]

• Vitamins

  An essential factor in the formation of blood clotting factors. Deficiency can lead to abnormal bleeding.

• Vitamin therapy

  The use of vitamins to prevent or cure disease. Many physicians are now recognizing the beneficial uses of anti-oxidant and other vitamins for a wide variety of conditions, often as a complementary therapy to accompany medication or other treatments. One variant on this theme, megavitamin therapy, is still rather controversial. Always consult your doctor before […]

• Vitamin requirements, infant

  Vitamins are organic substances that are essential in minute quantities for the proper growth, maintenance, and functioning of the baby. Vitamins must be obtained from food because the body cannot produce them. The exception is vitamin D, which can be produced by the skin when it is exposed to the sun. There are four fat-soluble […]

• Vitamin P

  An old name for substances now known as bioflavinoids. They are no longer considered to be vitamins by the strict definition of that word.

• Vitamin O

  Not a true vitamin but rather a pricey health supplement that is composed largely of salt water (plus some germanium, a trace element dangerous to health). The US Federal Trade Commission (FTC) charged the manufacturer of Vitamin O with fraud for touting it as a cure for cancer and heart disease. The FTC said advertisements […]

• Vitamin K

  particularly prothrombin and also factors VII, IX, and X. Vitamin K1 is made by plants, whereas vitamin K2 is of bacterial origin and is the important form for people. All other forms of vitamin K are converted to vitamin K2 in the body. There are a number of closely related compounds of the vitamin K2 […]

• Vitamin E

  In the ATBC cancer prevention trial, men given alpha-tocopherol (vitamin E) had a lower incidence of prostate cancer than men given a placebo. The vitamin E-treated group also had significantly lower death rates from prostate cancer. However, newer studies from a trial called SELECT showed that taking vitamin E can actually be harmful. According to […]

• Vitamin D3

  A vitamin produced by the body when exposed to ultraviolet light or obtained from dietary sources. Vitamin D3 is a hormone that has an important role in calcium and phosphorus metabolism. Technically, vitamin D3 is not a vitamin because the body can produce it. Also known as cholecalciferol.

• Vitamin D requirement

  for those 1-70 years of age, 600 IU daily; for those 71 years and older, 800 IU daily; and for pregnant and lactating women, 600 IU daily. The IOM further recommended that serum 25(OH)D levels of 20ng/mL (= 50 nmol/L) is adequate, and levels > 50ng/mL (= 125 nmol/L) could have potential adverse effects

• Vitamin D

  for those 1-70 years of age, 600 IU daily; for those 71 years and older, 800 IU daily; and for pregnant and lactating women, 600 IU daily. The IOM further recommended that serum 25(OH)D levels of 20ng/mL (= 50 nmol/L) is adequate, and levels > 50ng/mL (= 125 nmol/L) could have potential adverse effects As […]

• Vitamin C

  An essential nutrient found mainly in fruits and vegetables. The body requires vitamin C to form and maintain bones, blood vessels, and skin. Vitamin C is also known as ascorbic acid. Vitamin C is a water-soluble vitamin, one that cannot be stored by the body except in insignificant amounts. It must be replenished daily. Vitamin […]

• Vitamin B6

  A group of closely related chemical compounds with related names — pyridoxine, pyridoxal and pyridoxamine — that are transformed within the body to yet another form of vitamin B6, pyridoxal phosphate, that acts as a coenzyme. (A number of vitamins serve as coenzymes, substances that enhance the action of enzymes and thereby aid in catalyzing […]

• Vitamin B5

  Vitamin B5 is pantothenic acid, one of the less well known B vitamins, perhaps because it is widely distributed in nature. Pantothenic acid is virtually ubiquitous. It is present in foods as diverse as poultry, soybeans, yogurt, and sweet potatoes. No naturally occurring disease due to a deficiency of pantothenic acid has been identified, due […]

• Vitamin B3

  Mental disorientation, confusion, delusions and depression Death, if untreated. Pellagra, once a puzzle, was solved by Joseph Goldberger (1874-1929). Serving in the Public Health Service, Dr. Goldberger proposed that pellagra was due to a nutritional deficiency and in 1915 began experiments with Mississippi prison inmates (who “volunteered” in return for full pardons). Dr. Goldberger fed […]

• Vitamin B2

  1.7 mg (Intakes may be adjusted according to a physician’s instructions.) A milligram equals 1/1000 of a gram. A gram equals .0353 of an ounce. Side Effects From Overdose of Vitamin B2 Vitamin B2 is not known to cause overdose side effects because excessive amounts are not retained by the body. Interactions of Vitamin B2 […]

• Vitamin B15

  An old name for dimethylglycine (DMG, pangamic acid), which is no longer considered to be a vitamin by the strict definition of that word.

• Vitamin B12-responsive methylmalonicaciduria

  methylmalonicaciduria, long chain ketonuria, and intermittent hyperglycinemia.) Some but not all patients with methylmalonicaciduria respond to vitamin B12. An enzyme called methylmalonyl-CoA mutase is defective in the disease. This enzyme requires the presence of adenosylcobalamin, a form of vitamin B12. The metabolic block in methylmalonic acidemia occurs at methylmalonyl-CoA mutase and can be caused by […]

• Vitamin B12

  A vitamin important for the normal formation of red blood cells and the health of the nerve tissues. Undetected and untreated vitamin B12 deficiency can lead to anemia and permanent nerve and brain damage. Pernicious anemia is a blood disorder caused by inadequate vitamin B12 in the blood. Patients who have this disorder do not […]

• Vitamin B1

  An essential factor in the formation of blood clotting factors. Deficiency can lead to abnormal bleeding.

• Vitamin B — pantothenic acid

  This is one of the less well known B vitamins, perhaps because it is widely distributed in nature. Pantothenic acid is virtually ubiquitous. It is present in foods as diverse as poultry, soybeans, yogurt, and sweet potatoes. No naturally occurring disease due to a deficiency of pantothenic acid has been identified, due to the plentifulness […]

• Vitamin B — nicotinic acid

  Mental disorientation, confusion, delusions and depression Death, if untreated. Pellagra, once a puzzle, was solved by Joseph Goldberger (1874-1929). Serving in the Public Health Service, Dr. Goldberger proposed that pellagra was due to a nutritional deficiency and in 1915 began experiments with Mississippi prison inmates (who “volunteered” in return for full pardons). Dr. Goldberger fed […]

• Vitamin A deficiency

  14 million pre-school children have some eye damage due to VAD; 350 000 (or more) pre-school children become partially or totally blind every year from VAD; About 60% of these children die within a few months of going blind; VAD is associated with an increase in the severity of infections, particularly measles and diarrheal disease; […]

• Vitamin A

  An essential factor in the formation of blood clotting factors. Deficiency can lead to abnormal bleeding.

• Vital bodily function

  “Ostomy surgery is a life-enhancing procedure that restores a vital bodily function.”

• Vital

  Necessary to maintain life. For example, breathing is a vital function.

• Visual receptor

  The layer of rods and cones that are the visual cells of the retina.

• Visual pathway glioma

  A slow-growing benign tumor of the eye.

• Visual nerve pathways

  The optic nerves serving the eyes join behind the eyes just in front of the pituitary gland to form a cross-shaped structure called the optic chiasma. Within the optic chiasma some of the nerve fibers cross. The fibers from the nasal (inside) half of each retina cross over, but those from the temporal (outside) sides […]

• Visual field test

  Plaquenil), can also affect the visual field.

• Visual field

  The entire area that can be seen when the eye is directed forward, including that which is seen with peripheral vision. The visual field can be tested to measure the extent and distribution of the field of vision. The test may be done by a number of methods including what are termed confrontation, tangent screen […]

• Visual field

  Hydroxychloroquine is classified as an anti-malarial drug. It is similar to chloroquine (Aralen) and is useful in treating several forms of malaria as well as lupus erythematosus and rheumatoid arthritis. Its mechanism of action is unknown. Malarial parasites invade human red blood cells. Hydroxychloroquine may prevent malarial parasites from breaking down (metabolizing) hemoglobin in human […]

• Visual evoked response

  VER. A type of electrophysiologic retinal testing done to evaluate the retina and optic nerve by measuring the electrical potential resulting from a visual stimulus.

• Visual contrast sensitivity

  The ability to perceive differences between an object and its background.

• Visual acuity test

  This test measures how well you see at various distances. It is the familiar eye chart test. The eye chart itself — the usual one is called Snellen’s chart — is imprinted with block letters that line-by-line decrease in size, corresponding to the distance at which that line of letters is normally visible. The letters […]

• Visual acuity

  The clarity or clearness of vision, a measure of how well a person sees.

• Vision, tubular

  Tubular vision; Tunnel vision.

• Vision, macular

  The macula is a special area in the center of the retina, the light-sensitive layer of tissue at the back of the eye. As we read, light is focused onto our macula. There, millions of cells change the light into nerve signals that tell the brain what we are seeing. This is called our macular […]

• Vision, low

  Visual loss that cannot be corrected with eyeglasses or contact lenses and that interferes with daily living activities.

• Vision, central

  A process in which millions of cells change light into nerve signals that tell the brain what the person is seeing. As a person reads, drives, and performs other activities that require fine, sharp, straight-ahead vision, light is focused onto the macula in the center of the retina, the light-sensitive layer of tissue at the […]

• Vision therapy

  The use of special eye exercises to address eye defects, such as strabismus. Some vision therapists claim that eye exercises can help people with neurological or learning disabilities. Vision therapy is not proven for the latter use, although some patients do report improvement.

• Viscus

  An internal organ of the body, specifically one within the chest (as the heart or lungs) or abdomen (as the liver, pancreas or intestines). “Viscus” is the Latin word for “an organ of the body.” The plural of “viscus” is “viscera.”

• Visceral pericardium

  The inner layer of the pericardium.

• Visceral leishmaniasis

  the British pathologist William Boog Leishman who in 1903 wrote about the protozoa that causes kala-azar and the researcher C. Donovan, who made the same discovery independently the same year.

• Visceral

  Referring to the viscera, the internal organs of the body, specifically those within the chest (as the heart or lungs) or abdomen (as the liver, pancreas or intestines). In a figurative sense, something “visceral” is felt “deep down.” It is a “gut feeling.”

• Viscera

  The internal organs of the body, specifically those within the chest (as the heart or lungs) or abdomen (as the liver, pancreas or intestines). The singular of “viscera” is “viscus” meaning in Latin “an organ of the body.”

• Viruses

  Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.

• Virus, xenotropic

  A virus that can grow in the cells of a species foreign to the normal host species, a species different from that which normally hosts it. Xeno- means foreign while -tropic refers to growth. So xeno- + -tropic = capable of growing in a foreign environment.

• Virus, respiratory syncytial

  See Respiratory syncytial virus.

• Virus, Nipah

  A virus that infects pigs and people in whom it causes a sometimes fatal form of viral encephalitis (brain inflammation). Nipah is the name of the first village the virus struck near Kuala Lumpur in Malaysia. The Nipah virus is similar to Hendra virus that was discovered in Australia in 1994. Nipah virus caused a […]

• Virus, lymphadenopathy-associated

  Virus, human immunodeficiency.

• Virus, lymphadenopathy

  Virus, human immunodeficiency.

• Virus, human lymphotropic, type III

  Virus, human immunodeficiency.

• Virus, human immunodeficiency (HIV)

  The cause of AIDS. HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus. No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase, the virus uses its RNA as a template […]

• Virus, attenuated

  a virus that is capable of stimulating an immune response and creating immunity but not of causing illness.

• Virus

  A microorganism that is smaller than a bacterium that cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations); this ability to mutate is responsible for the ability of […]

• Virulence

  The ability of an agent of infection to produce disease. The virulence of a microorganism is a measure of the severity of the disease it causes.

• Virtual colonoscopy

  A method for examining the colon by taking a series of x-rays and then using a computer to reconstruct three-dimensional pictures (a CT scan) of the interior surfaces of the colon from these x-rays. The pictures can be saved, manipulated to better viewing angles, and reviewed after the procedure. The procedure requires a 48-hour low-fiber […]

• Virilize

  (1) failure of the ovaries to produce, develop or release eggs (ova); (2) ovary enlargement; (3) failure to menstruate; (4) irregular menstruation; (5) obesity; and (6) infertility. It must be noted that failure to menstruate is normal before puberty, during pregnancy, during early lactation and after menopause. It is probably abnormal at other times and […]

• Virginal membrane

  A thin membrane which completely or partially occludes the vaginal opening. This fold of mucous membrane is usually present at birth at the orifice of the vagina. In medicine, it is called the vaginal membrane or the hymen. Hymen is a Greek word meaning “skin” or “membrane.” The ancient Greeks applied the word “hymen” to […]

• Viremia

  The presence of a virus in the blood. Viremia is analogous to bacteremia (the presence of bacteria in the blood) and parasitemia (the presence of a parasite in the blood). Viremia, bacteremia, and parasitemia are all forms of sepsis (bloodstream infection).

• Viral infection

  Infection caused by the presence of a virus in the body. Depending on the virus and the person’s state of health, various viruses can infect almost any type of body tissue, from the brain to the skin. Viral infections cannot be treated with typical antibiotics (antibacterial antibiotics); in fact, in some cases the use of […]

• Viral hepatitis

  Liver inflammation caused by a virus. Specific hepatitis viruses have been labeled A, B, C, D, and E. Some other viruses, such as the Epstein-Barr virus and cytomegalovirus, can also cause hepatitis, but the liver is not their primary target.

• Viral hemorrhagic fever

  the arenaviruses, filoviruses, bunyaviruses, and flaviviruses. The arenaviruses include the Lassa fever virus and Machupo, Junin, Guanarito, and Sabia hemorrhagic fever viruses. Among the filoviruses are the notorious Ebola virus and Marburg virus. The bunyaviruses include Rift Valley fever (RVF), Crimean-Congo hemorrhagic fever (CCHF), and hantaviruses. The viruses of yellow fever and dengue are Among […]

• Viral encephalitis

  Inflammation of the brain as a result of virus infection. There are many viruses that cause viral encephalitis.

• Viral

  Of or pertaining to a virus. For example, if a person has a viral rash, the rash was caused by a virus.

• Vinyl chloride

  A substance used in manufacturing plastics that is known to be toxic and carcinogenic (cancer-causing). Dangerous exposure to vinyl chloride occurs mainly in the workplace. Breathing high levels of vinyl chloride for short periods of time can cause dizziness, sleepiness, unconsciousness and, at extremely high levels, death. Breathing vinyl chloride for long periods of time […]

• Vincent stomatitis

  This is trench mouth, a progressive painful infection with ulceration, swelling and sloughing off of dead tissue from the mouth and throat due to the spread of infection from the gums. Certain germs (including fusiform bacteria and spirochetes) have been thought to be involved, but the full story behind this long- known disease is still […]

• Vincent infection

  This is trench mouth, a progressive painful infection with ulceration, swelling and sloughing off of dead tissue from the mouth and throat due to the spread of infection from the gums. Certain germs (including fusiform bacteria and spirochetes) have been thought to be involved, but the full story behind this long- known disease is still […]

• Vincent gingivitis

  This is trench mouth, a progressive painful infection with ulceration, swelling and sloughing off of dead tissue from the mouth and throat due to the spread of infection from the gums. Certain germs (including fusiform bacteria and spirochetes) have been thought to be involved, but the full story behind this long-known disease is still not […]

• Vincent angina

  This is trench mouth, a progressive painful infection with ulceration, swelling and sloughing off of dead tissue from the mouth and throat due to the spread of infection from the gums. Certain germs (including fusiform bacteria and spirochetes) are thought to be involved. Vincent’s angina is best treated with the antibiotic penicillin. This condition is […]

• Villus

  1. A tiny finger-like or hair-like projection. 2. A small vascular protrusion. Villus is the Latin word for shaggy hair or fleece. The plural is villi.

• Villi

  Plural of villus, a tiny finger-like or vascular projection.

• Vidian neuralgia

  Characterized by the absence of sustained periods of remission, chronic cluster headache may start with no past history of cluster headaches, or it may emerge several years after the patient has experienced an episodic pattern of cluster headaches. The episodic and acute forms of cluster headache may transform into one another, so it seems most […]

• Video-assisted surgery

  Surgery that is aided by the use of a video camera that projects and enlarges the image on a television screen. Also called video-assisted resection.

• Video-assisted resection

  Surgery that is aided by the use of a video camera that projects and enlarges the image on a television screen. Also called video-assisted surgery.

• Vibrotactile aid

  A mechanical instrument attached to the head, near the ear(s), that helps individuals who are deaf to detect and interpret sounds through their sense of touch. It is called a vibrotactile aid because it serves as an aid by permitting a person to feel the vibrations, in this case, of sounds.

• Vibrio vulnificus

  CDC.gov. Vibrio vulnificus.

• Vibrio cholerae

  One of the Vibrio bacteria, V. cholerae (as the name implies) is the agent of cholera, a devastating and sometimes lethal disease with profuse watery diarrhea. Like other Vibrio, V. cholerae moves about actively. The word “vibrio” in Latin means “to quiver.”

• Vibrio

  A group of bacteria that includes Vibrio cholerae, the agent that causes cholera. Other species are common in salt and fresh water as well as soil. Vibrio move about particularly actively.

• Vibration white finger

  The original name for a painful and potentially disabling condition of the fingers, hands, and arms due to vibration. Known now preferably as the hand-arm vibration syndrome. In this syndrome, there is initially a tingling sensation in the fingers with numbness. The fingers then become white and swollen when cold and then red and painful […]

• VBAC

  Vaginal Birth After Cesarian section. Although the abbreviation VBAC (pronounced VEE-back) does not appear in standard medical dictionaries, it is in active international use.

• vCJD

  Stands for variant Creutzfeldt-Jakob disease, a human disease thought due to the same infectious agent as bovine spongiform encephalopathy (BSE), or mad cow disease. Both the human and bovine disorders are invariably fatal brain diseases with unusually long incubation periods measured in years, and are caused by an unconventional transmissible agent, a prion, resulting in […]

• VCU

  Voiding cystourethrography. Or voiding cystourethrogram.

• Veterinary medicine

  The medical science concerned with the diagnosis, treatment and prevention of diseases in animals. Aside from diagnosing and treating sick and injured animals, veterinarians prevent the transmission of animal diseases to people, and advise owners on the proper care of animals. Veterinarians work to ensure a safe food supply by maintaining the health of agricultural […]

• Vestigial

  Referring to a vestige (remnant) or a primitive structure and no longer believed to be important. For example, the appendix is considered a vestigial organ, and some infants are born with vestigial tails.

• Vestibulocochlear nerve

  A nerve that is responsible for the sense of hearing and that is also pertinent to the senses of balance and body position. Problems with the vestibulocochlear nerve may result in deafness, tinnitus (ringing or noise in the ears), dizziness, vertigo, and vomiting. The vestibulo-cochlear nerve is the eighth cranial nerve.

• Vestibule, vaginal

  The vaginal opening is called the vestibule of the vagina. In medicine, a vestibule is a space or cavity at the entrance to a canal, channel, tube, vessel. In ancient Rome, the “vestibulum” was an entrance or enclosed porch leading into the house. The vagina is a muscular canal extending from the cervix to the […]

• Vestibule of the ear

  A cavity in the middle of the bony labyrinth in the inner ear.

• Vestibule

  In medicine and dentistry, a space or cavity at the entrance to a canal, channel, tube, or vessel. For instance, the front of the mouth is a vestibule.

• Vestibular system

  A system that is composed of the vestibular apparatus, the vestibulocochlear nerve, and the parts of the brain that interpret and respond to information derived from those structures.

• Vertigo: Treatment, Symptoms, and Causes

  Have you tried vestibular rehabilitation exercises (Cawthorne head exercises or the Epley maneuver) for your vertigo? Did they help? View 5 Comments • Submit » Vertigo is a feeling that you are dizzily turning around or that your surroundings are dizzily turning about you. Vertigo is usually due to a problem with the inner ear […]

• Vestibular neuronitis

  Inflammation of the vestibular nerve, the nerve running to the vestibule. (The vestibule is in the inner ear. Like an internal carpenter’s level, it and the semicircular canals work with the brain to sense, maintain, and regain balance and a sense of where the body and its parts are positioned in space.) Vestibular neuronitis is […]

• Vestibular disorders

  Disorders of the body’s balance (vestibular) system in the inner ear due to a tremendous range of conditions including vertigo, Meniere’s disease, acoustic neuroma, multiple sclerosis, syphilis, trauma, ear infections, medications toxic to the ear (ototoxic drugs), epilepsy (seizure disorders), etc. Diagnosis is by neurological tests, including Electronystagmography (ENG), in which the patient’s response to […]

• Vestibular apparatus

  The vestibule and three semicircular canals of the inner ear. Like an internal carpenter’s level, these structures work with the brain to sense, maintain, and regain balance and a sense of where the body and its parts are positioned in space.

• Vestibular

  1) Having to do with a structure that is a vestibule (entrance), such as the vestibule of the ear. 2) Having to do with the body’s system for maintaining equilibrium.

• Vessel, efferent

  A vessel that carries blood away from the heart. Hence, an efferent vessel is an artery or an arteriole (a little artery).

• Vessel, afferent

  A vessel that carries blood toward the heart. A vein or venule.

• Vessel

  A tube in the body that carries fluids. Examples of vessels are blood vessels and lymph vessels.

• Vesiculography

  The use of special X-ray equipment and a dye to examine the seminal vesicles and related structures. Vesiculography is most often used when prostate disease or cancer is suspected.

• Vesiculitis

  Inflammation of a vesicle, particularly of the seminal vesicles behind the male bladder.

• Vesicular rickettsiosis

  A mild infectious disease first observed in New York City, caused by Rickettsia akari, transmitted from its mouse host by chigger or adult mite bites. There is fever, a dark spot that becomes a small ulcer at the site of the bite, swollen glands (lymphadenopathy) in that region, and a raised blistery (vesicular) rash. Also […]

• Vesicular

  Referring to the presence of one or more vesicles. For example, a vesicular rash features small blisters on the skin.

• Vesicoenteric

  Pertaining to both the urinary bladder and intestine or to a communication between them, as in a vesicoenteric fistula. Synonymous with vesicointestinal.

• Vesicle, seminal

  One of two structures that are about 5 cm long and are located behind the bladder and above the prostate gland. The seminal vesicles contribute fluid to the ejaculate.

• Vesicle

  In dermatology, a vesicle is a small blister, as on the skin. Vesicles also occur on the mucous membranes, such as the buccal mucosa (the lining of the mouth). Vesicles are less than 0.5 centimeters in diameter. In anatomy, a vesicle is any small pouch. For example, the seminal vesicles are a pair of pouch-like […]

• Vesicatory

  A substance that causes tissue blistering. Also referred to as a vesicant.

• Vesicant

  A substance that causes tissue blistering. Also known as vesicatory.

• Vesical

  Refers to the urinary bladder. The word comes from the Latin vesica meaning a bag or bladder.

• VES (Voluntary Euthanasia Society)

  The first society of its kind in the world — its founders included doctors, lawyers and churchmen — the VES was set up in England in 1935. The announced aim of the VES is to make it legal for a competent adult suffering unbearably from an incurable illness to receive medical help to die at […]

• Very low calorie diet (VLCD)

  The Very low calorie diet (VLCD) is a doctor-supervised weight loss plan that uses commercially prepared formulas (usually shakes and/or bars) to achieve significant short-term weight loss. The shakes or bars typically replace all food consumption for a period of weeks to months. Very low calorie diets generally contain about 800 calories per day, or […]

• Vertigo, recurrent aural

  A condition, also known as Meniere’s disease, with recurrent vertigo accompanied by ringing in the ears (tinnitus) and deafness. Symptoms include vertigo, dizziness, nausea, vomiting, loss of hearing (in the affected ear). Meniere’s syndrome or disease is due to dysfunction of the semi-circular canals (endolymphatic sac) in the inner ear. The treatment of Meniere’s disease […]

• Vertigo, benign paroxysmal positional (BPPV)

  A balance disorder that results in the sudden onset of dizziness, spinning, or vertigo when moving the head.

• Vertigo

  Dizziness, Lightheadedness, and Unsteadiness.

• Vertical transmission

  Passage of a disease-causing agent (pathogen) from mother to baby during the period immediately before and after birth. Transmission might occur across the placenta, in the breast milk, or through direct contact during or after birth. For example, HIV can be a vertically transmitted pathogen. Also known as perinatal transmission.

• Vertical

  In anatomy, upright. As opposed to horizontal. For a more complete listing of terms used in medicine for spatial orientation, please see the entry to “Anatomic Orientation Terms”.

• Vertex

  The top of the head. For example, in a vertex presentation at birth, the top of the baby’s head emerges first.

• Vertebroplasty

  A nonsurgical method for repairing osteoporosis back fractures, such as vertebral compression fractures. Vertebroplasty is performed by a radiologist, without surgery, and involves inserting a glue-like material into the center of the collapsed spinal vertebra to stabilize and strengthen the crushed bone. The material is inserted through anesthetized skin with a needle and syringe, entering […]

• Vertebral rib

  The lower five ribs do not directly connect to the sternum and are known as false ribs. The upper three false ribs connect to the costal cartilages of the ribs just above them. The last two false ribs, however, usually have no ventral attachment (no anchor at all in front) and are called vertebral, fluctuating, […]

• Vertebral compression fracture

  A fracture that collapses a spinal vertebra as a result of the compression of bone, leading to collapse of the vertebrae much like a sponge collapses under the pressure of one’s hand. Although they may occur without pain, such vertebral fractures often cause a severe, band-like pain that radiates from the spine around both sides […]

• Vertebral column

  small, rudimentary vertebrae that fuse together. Also known as the spinal column.

• Vertebral artery

  One of two key arteries located in the back of the neck that carry blood from the heart to the brain, spine, and neck muscles.

• Vertebral arch

  A circle of bone around the canal through which the spinal cord passes. A vertebral arch is composed of a floor at the back of the vertebra, walls (the pedicles), and a roof where two laminae join.

• Vertebrae, thoracic

  The 12 thoracic vertebrae are situated between the cervical (neck) vertebrae and the lumbar vertebrae. The thoracic vertebrae are represented by the symbols T1 through T12. The thoracic vertebrae provide attachment for the ribs and make up part of the back of the thorax (the chest).

• Vertebrae, sacral

  There are 5 sacral vertebral bones. They are represented by the symbols S1 through S5 and are situated between the lumbar vertebrae and the coccyx (the lowest segment of the vertebral column). The sacral vertebrae are normally fused to form the sacrum.

• Vertebrae, lumbar

  There are 5 lumbar vertebrae. The lumbar vertebrae are situated between the thoracic vertebrae and the sacral vertebrae in the spinal column. The 5 lumbar vertebrae are represented by the symbols L1 through L5.

• Vertebrae, coccygeal

  The coccyx, the small tail-like bone at the bottom of the spine near the anus, is made up of 3-5 (average of 4) rudimentary vertebrae.

• Vertebrae, cervical

  The cervical (neck) vertebrae are the upper 7 vertebrae in the spinal column (the vertebral column). They are designated C1 through C7 from the top down. C1 is called the atlas. It supports the head and is named for the Greek god Atlas who was condemned to support the earth and its heavens on his […]

• Vertebrae

  Cervical vertebrae; Coccygeal vertebrae; Lumbar vertebrae; Sacral vertebrae; and Thoracic vertebrae.

• Vertebra, second cervical

  The second cervical vertebra is called the axis. It is so-named because the uppermost cervical vertebra (called the atlas) rotates about the odontoid process of the second cervical vertebra. The joint between the axis and atlas is a pivot type of joint. It allows the head turn. The Latin word “axis” means axle or pole. […]

• Vertebra, prominent

  The 7th cervical (neck) vertebra (C7) is sometimes called the prominent vertebra because of the length of its spinous process (the projection off the back of the vertebral body). The spinous process of the top thoracic vertebra (T1) just below C7 is sometimes even more prominent than that of the “prominent vertebra”.

• Vertebra, first cervical

  The first cervical (neck) vertebra is called the atlas. It supports the head. The atlas bone is named for the Greek god Atlas who was condemned to support the earth and its heavens on his shoulders. (Because the god Atlas often adorned maps, a compilation of maps came to be known as an atlas).

• Vertebra

  A vertebra is one of 33 bony segments that form the spinal column of humans. There are 7 cervical, 12 thoracic, 5 lumbar, 5 sacral (fused into one sacrum bone) and 4 coccygeal (fused into one coccyx bone).

• Version

  1. In obstetrics, the process of turning the fetus. A cephalic version brings the fetal head into the birth canal. 2. In gynecology, the tilting of the uterus. Uterine retroversion indicates the uterus is tilted backwards. 3. In ophthalmology, the conjugate rotation (turning) of both eyes in the same direction. The special uses of the […]

• Verruca

  A wart by another name, a local growth of the outer layer of the skin (the epidermis) caused by a virus. The virus of warts (a human papillomavirus) is transmitted by contact. The contact can be with a wart on someone else or one on oneself (autoinoculation). Warts that occur on the hands or feet […]

• Vernix caseosa

  A white cheesy substance that covers and protects the skin of the fetus and is still all over the skin of a baby at birth. Vernix caseosa is composed of sebum (the oil of the skin) and cells that have sloughed off the fetus’ skin. “Vernix” is the Latin word for “varnish.” The vernix varnishes […]

• Vernix

  A white, cheesy substance that covers and protects the skin of a fetus. Vernix is still all over the skin of a baby at birth. Vernix is composed of sebum (skin oil) and cells that have sloughed off the skin of the fetus. More formally known as vernix caseosa.

• Verbal child abuse

  Also known as emotional child abuse, this is the third most frequently reported form of child abuse (after child neglect and physical child abuse), accounting 17% of all cases of child abuse. It is likely that emotional child abuse is greatly underreported, since it can be difficult to detect and difficult to document. Emotional child […]

• VER

  Visual evoked response. A type of electrophysiologic retinal testing.

• Venule

  A little vein that goes from a capillary to a vein.

• Ventriculopleural shunt

  A shunt that drains fluid from a cerebral ventricle into the pleural (chest) cavity. The shunt is designed to relieve hydrocephalus (“water on the brain”).

• Ventricular tachycardia

  An abnormal heart rhythm that is rapid and regular and that originates from an area of the lower chamber (ventricle) of the heart. Ventricular tachycardias can be life-threatening arrhythmias that are commonly associated with damage to the heart muscle due to coronary artery disease.

• Ventricular septum

  The wall between the two lower chambers (ventricles) of the heart.

• Ventricular septal defect (VSD)

  A hole in the septum (the wall) between the lower chambers of the heart (the ventricles). Ventricular Septal Defect is the most common type of heart malformation (congenital heart disease). At least 1 baby in every 500 is born with a VSD. A VSD lets blood from the left ventricle (where it is under relatively […]

• Ventricular fibrillation

  An abnormal and irregular heart rhythm in which there are rapid uncoordinated fluttering contractions of the lower chambers (ventricles) of the heart. Ventricular fibrillation disrupts the synchrony between the heartbeat and the pulse beat. Ventricular fibrillation is commonly associated with heart attacks and scarring of the heart muscle from previous heart attacks. Ventricular fibrillation is […]

• Ventricular assist device

  A mechanical pump that takes over the function of the damaged ventricle of the heart and restores normal blood flow. Left ventricular assist devices (LVADs) were originally developed for patients with heart disease from which they were not expected to recover and who needed mechanical support as a bridge to a heart transplant. LVADs were […]

• Ventricular arrhythmias

  Abnormal rapid heart rhythms (arrhythmias) that originate in the lower chambers of the heart (the ventricles). Ventricular arrhythmias include ventricular tachycardia and ventricular fibrillation. Both are life threatening arrhythmias most commonly associated with heart attacks or scarring of the heart muscle from previous heart attack.

• Ventricular

  Pertaining to the ventricles, the lower chambers of the heart, as in ventricular fibrillation and ventricular septal defect.

• Ventricles

  1, The right ventricle and the left ventricle, the lower two chambers of the heart. 2. Two or more of the four connected spaces within the central portion of the brain.

• Ventricle, third

  One cavity in a system of four communicating cavities within the brain that are continuous with the central canal that contains the spinal cord. The third ventricle is a median (midline) cavity in the brain and is bounded by the thalamus and hypothalamus on either side. It communicates anteriorly (in front) with the lateral ventricles, […]

• Ventricle, right

  The ventricles are the two lower chambers of the heart. The right ventricle is the chamber that receives blood from the right atrium and pumps it under low pressure into the lungs via the pulmonary artery.

• Ventricle, left

  The ventricles are the two lower chambers of the heart. The left ventricle is the chamber that receives blood from the left atrium and pumps it out under high pressure to the body via the aorta.

• Ventricle, lateral

  A communicating cavity in the brain that is part of a system of four communicating cavities that are continuous with the central canal of the spinal cord. The two lateral ventricles are located in the cerebral hemispheres, one in each hemisphere. Each con

• Ventricle, heart

  One of the two lower chambers of the heart. The right ventricle receives blood from the right atrium and pumps it into the lungs via the pulmonary artery, and the left ventricle receives blood from the left atrium and pumps it into the circulation system via the aorta.

• Ventricle, fourth

  One cavity in a system of four communicating cavities within the brain, which are continuous with the central canal of the spinal cord. The fourth ventricle is the most inferior (lowest) of these. It extends from the aqueduct of the midbrain to the central canal of the upper end of the spinal cord, with which […]

• Ventricle, cerebral

  One of a system of four communicating cavities within the brain that are continuous with the central canal of the spinal cord. They include two lateral ventricles in the cerebral hemispheres, each consisting of a triangular central body and four horns. The lateral ventricles communicate with the third ventricle through an opening called the interventricular […]

• Ventricle, brain

  two lateral ventricles, the third ventricle, and the fourth ventricle. The lateral ventricles are in the cerebral hemispheres. Each lateral ventricle consists of a triangular central body and four horns. The lateral ventricles communicate with the third ventricle through the interventricular foramen (opening). The third ventricle is a median (midline) cavity in the brain, bounded […]

• Ventricle

  A chamber of an organ. For example, the four connected cavities in the central portion of the brain are called ventricles.

• Ventral

  Pertaining to the front or anterior of any structure. The ventral surfaces of the body include the chest, abdomen, shins, palms, and soles. Ventral is as opposed to dorsal. From the Latin “venter” meaning belly. For a more complete listing of terms used in medicine for spatial orientation, please see the entry to “Anatomic Orientation […]

• Ventilator

  A machine that mechanically assists a patient in the exchange of oxygen and carbon dioxide, a process sometimes referred to as artificial respiration.

• Ventilation, positive pressure

  The provision of oxygen under pressure by a mechanical respirator, a machine designed to improve the exchange of air between the lungs and the atmosphere. The device is basically designed for administering artificial respiration, especially for a prolonged period, in the event of inadequate spontaneous ventilation or respiratory paralysis. The mechanical ventilator was invented in […]

• Ventilation, mechanical

  Use of a machine called a ventilator or respirator to improve the exchange of air between the lungs and the atmosphere.

• Ventilation

  The exchange of air between the lungs and the atmosphere so that oxygen can be exchanged for carbon dioxide in the alveoli (the tiny air sacs in the lungs).

• Venous line, central

  the cuffed or tunnelled line and the reservoir long line that ends in a rubber bulb or reservoir. The possible complications of a central venous line include air in the chest (pneumothorax) due to a punctured lung, bleeding in the chest (hemothorax), fluid in the chest (hydrothorax), bleeding into or under the skin (hematoma) and […]

• Venous claudication

  Limping and/or pain due to inadequate venous drainage, poor return of blood by the veins, from the legs.

• Venous catheterization

  The insertion of a tiny tube (catheter) into a peripheral or central vein to deliver fluids or medication. Venous catheterization is the most frequently used method for administration of IV fluids. The most common complication of venous catheterization is infection at the site of the catheter (catheter sepsis).

• Venous aneurysm

  A localized widening and bulging of a vein. At the area of a venous aneurysm, the vein wall is weakened and may rupture.

• Venomous

  1. Full of venom. 2. Having venom, like some snakes and insects. 3. By extension, noxious, as a venomous tongue.

• Venom, scorpion

  The potent poison of the scorpion. A sting can be fatal to a person who is allergic to it. A scorpion is an insect that has an elongated body and a segmented, curved tail tipped with a venomous stinger. Grasping, fingerlike first appendages are other typical features. The toxicity of scorpion venom varies by species. […]

• Venom

  A poison, particularly one secreted by an animal. Examples are bee venom, snake venom, scorpion venom, and spider venom. Snake venom is also called venin.

• Venipuncture

  The puncture of a vein with a needle to withdraw blood. Also called phlebotomy or, more often, a blood draw.

• Venereal wart

  A wart that is confined primarily to the moist skin of the genitals. These warts are due to viruses belonging to the family of human papilloma viruses (HPVs) which are transmitted through sexual contact. The virus can also be transmitted from mother to baby during childbirth. Most people infected with HPV have no symptoms but […]

• Venereal Disease Research Laboratory test

  A blood test for syphilis. Venereal Disease Research Laboratory is commonly abbreviated VDRL. A negative (“nonreactive”) VDRL is compatible with a person not having syphilis. However, a person may a negative VDRL and still have syphilis since, in the early stages of the disease, the VDRL often gives negative results. This is called a false […]

• Venereal

  Having to do with sexual contact. For example, a venereal disease is a sexually transmitted disease.

• Vena cava, superior

  A large vein that receives blood from the head, neck, upper extremities, and thorax and empties it into the right atrium of the heart.

• Vena cava, inferior

  The large vein that receives blood from the lower extremities, pelvis, and abdomen and then empties that blood into the right atrium of the heart.

• Velpeau hernia

  A protrusion of tissue in front of the femoral blood vessels in the groin. Treatment is via ‘surgery.

• Veisalgia

  Medical term for a hangover. From the Norwegian kveis (uneasiness following debauchery) + the Greek algia (pain).

• The orbital cavity is drained by paired veins called the superior and inferior ophthalmic veins. The superior ophthalmic vein arises at the inner angle of orbit and follows the course of ophthalmic artery into the cavernous sinus, a greatly dilated (widened) channel of venous blood. The inferior ophthalmic vein arises from a venous network at […]

• Vein, superior vena cava

  A large vein that receives blood from the head, neck, upper extremities, and thorax and empties it into the right atrium of the heart.

• Vein, small saphenous

  The smaller of the two saphenous veins, the principal veins that run up the leg superficially (near the surface). The small saphenous vein, runs behind the outer malleolus (the protuberance on the outside of the ankle joint), comes up the back of the leg and joins the popliteal vein in the space behind the knee […]

• Vein, splenic

  A vein that is formed by the union of several small veins draining blood from the stomach, pancreas and spleen. The splenic vein is a major contributor to the portal vein which goes to the liver.

• Vein, pulmonary

  One of four vessels that carry aerated blood from the lungs to the left atrium of the heart. (The four are the right and left superior and inferior pulmonary veins). The pulmonary veins are the only veins that carry bright red oxygenated blood.

• Vein, portal

  A large vein that carries blood from the stomach and the intestines to the liver. The portal vein is formed by the union of the splenic and superior mesenteric veins. It conveys venous blood to the liver for detoxification before the blood is returned to the circulation via the hepatic veins.

• Vein, mesenteric

  One of the large veins which return blood from the intestines. The inferior (lower) mesenteric vein empties into the splenic vein. The superior (upper) mesenteric vein then joins the splenic vein to create the portal vein which goes to the liver.

• Vein, large saphenous

  The larger of the two saphenous veins, the principal veins that run up the leg superficially (near the surface). The large saphenous vein goes from the foot all the way up to the saphenous opening, an oval aperture in the broad fascia of the thigh, a fibrous membrane through which the vein passes. The other […]

• Vein, internal jugular

  The deeper of the two jugular veins in the neck that drain blood from the head, brain, face and neck and convey it toward the heart. The internal jugular vein collects blood from the brain, the outside of the face and the neck. It runs down the inside of the neck outside the internal and […]

• Vein, inferior vena cava

  A large vein that receives blood from the lower extremities, pelvis and abdomen and empties it into the right atrium of the heart.

• Vein, hepatic

  One of the veins which drains blood from the liver.

• Vein, great saphenous

  The larger of the two saphenous veins, the principal veins that run up the leg superficially (near the surface). The great saphenous vein goes from the foot all the way up to the saphenous opening, an oval aperture in the broad fascia of the thigh, a fibrous membrane through which the vein passes. The other […]

• Vein, external jugular

  The more superficial of the two jugular veins situated on each side of the neck. The other is the internal jugular vein. They drain blood from the head, brain, face and neck and convey it toward the heart. The external jugular vein collects most of the blood from the outside of the skull and the […]

• Vein, central retinal

  The blood vessel that carries blood away from the retina of the eye. The counterpart to the central retinal vein is the central retinal artery, the vessel that carries blood into the eye and supplies nutrition to the retina.

• Vein, brachial

  A vein that accompanies the brachial artery between the shoulder and the elbow. The route of the brachial artery is from the shoulder down to the elbow, whereas that of the brachial vein is in the reverse direction — from the elbow back up to the shoulder. Veins often appear to accompany arteries while the […]

• Vein of Galen aneurysm

  A congenital malformation of blood vessels of the brain. Specifically, an arteriovenous (AV) malformation in which blood shunts from cerebral arteries into a dilated vein of Galen (an internal cerebral vein). In newborns this shunt can cause high cardiac output and heart failure. In infants this AV malformation can obstruct the Aqueduct of Sylvius, a […]

• Vein

  A blood vessel that carries blood that is low in oxygen content from the body back to the heart. The deoxygenated form of hemoglobin (deoxy-hemoglobin) in venous blood makes it appear dark. Veins are part of the afferent wing of the circulatory system, which returns blood to the heart. In contrast, an artery is a […]

• VEGF

  Vascular endothelial growth factor, a substance made by cells that stimulates the formation of new blood vessels, a process called angiogenesis. VEGF also acts as a mitogen for vascular endothelial (vessel lining) cells, stimulating these cells to divide and multiply. VEGF is a polypeptide. It is structurally related to platelet-derived growth factor (PDGF). The gene […]

• Vectrin

  Brand name for minocycline.

• Vector, cloning

  A fragment of DNA into which another DNA fragment can be integrated. Cloning vectors are used to introduce foreign DNA into host cells, where that DNA can be reproduced (cloned) in large quantities. Examples of cloning vectors are plasmids, cosmids, bacterial artificial chromosomes (BACs), and yeast artificial chromosomes (YACs).

• Vector

  In medicine, a carrier of disease or of medication. For example, in malaria a mosquito is the vector that carries and transfers the infectious agent. In molecular biology, a vector may be a virus or a plasmid that carries a piece of foreign DNA to a host cell.

• VDRL test

  A blood test for syphilis (VDRL stands for Venereal Disease Research Laboratory) that detects an antibody that is present in the bloodstream when a patient has syphilis. A negative (nonreactive) VDRL is compatible with a person not having syphilis, but in the early stages of the disease, the VDRL often gives false negative results. Conversely, […]

• VCUG

  Voiding cystourethrography. Or voiding cystourethrogram.

• Vaccination

  Injection of a killed microbe in order to stimulate the immune system against the microbe, thereby preventing disease. Vaccinations, or immunizations, work by stimulating the immune system, the natural disease-fighting system of the body. The healthy immune system is able to recognize invading bacteria and viruses and produce substances (antibodies) to destroy or disable them. […]

• Vaccination, anthrax

  A series of six shots over six months and booster shots annually, the anthrax vaccine now in use in the USA was first developed in the 1950s and approved by the Food and Drug Administration for general use in 1970. It is produced by the Michigan Biologic Products Institute of Michigan’s Department of Health and […]

• Vasopressin

  A relatively small (peptide) molecule that is released by the pituitary gland at the base of the brain after being made nearby (in the hypothalamus). Vasopressin has an antidiuretic action that prevents the production of dilute urine (and so is antidiuretic). A syndrome of inappropriate secretion of vasopressin which results in the inability to put […]

• Vasomotor rhinitis

  Inflammation of the nose (rhinitis) due to abnormal nerve control of the blood vessels in the nose. Vasomotor rhinitis is not allergic rhinitis. Decongestant medications are used to temporarily reduce swelling of sinus and nasal tissues leading to an improvement of breathing and a decrease in obstruction.

• Vasomotor

  Relating to the nerves and muscles that cause blood vessels to constrict or dilate.

• Vasodilators

  Agents that act as blood vessel dilators (vasodilators) and open vessels by relaxing their muscular walls. For example, nitroglycerin is a vasodilator. So are the ACE (angiotensin converting enzyme) inhibitors.

• Vasodilation

  Widening of blood vessels that results from relaxation of the muscular walls of the vessels. What widens in vasodilation is actually the diameter of the interior (lumen) of the vessel. The opposite of vasodilation is vasoconstriction.

• Vasodepressor syncope

  The temporary loss of consciousness in a particular kind of situation. (Syncope is temporary loss of consciousness or, in plain English, fainting). The situations that trigger this reaction are diverse and include having blood drawn, straining while urinating or defecating or coughing. The reaction also can be due to the emotional stress of fear or […]

• Vasoconstriction

  Narrowing of the blood vessels that results from contraction of the muscular walls of the vessels. The opposite of vasoconstriction is vasodilation.