Literally, the stiffness of death. The rigidity of a body after death. Rigor mortis is a good example of a Latin term (one in this case that was coined in the 19th century) remaining intact in contemporary medical usage (and crime writing).
Rigor mortis is due to a biochemical change in the muscles that occurs several hours after death, though the time of its onset after death depends on the ambient temperature. The biochemical basis of rigor mortis is hydrolysis in muscle of ATP, the energy source required for movement. Without ATP, myosin molecules adhere to actin filaments and the muscles become rigid.
- Ring chromosome
A structurally abnormal chromosome in which the end of each chromosome arm has been lost and the broken arms have been reunited to form a ring. A ring chromosome is denoted by the symbol r.
- Ring vaccination
The vaccination of all susceptible individuals in a prescribed area around an outbreak of an infectious disease. Ring vaccination controls an outbreak by vaccinating and monitoring a ring of people around each infected individual. The idea is to form a buffer of immune individuals to prevent the spread of the disease. Ring vaccination was used […]
- Ring, intrastromal corneal
A plastic ring that is designed to be implanted in the cornea, the transparent structure at the front of the eye, to flatten the cornea and thereby reduce the degree of nearsightedness (myopia). The ring is placed in the corneal stroma, the middle of the five layers of the cornea.
- Ringing in the ears
Medically called tinnitus, can be due to many causes including ear infections, fluid in the ears, Meniere syndrome (the combination of tinnitus and deafness), some medications such as aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs), aging, and ear trauma (such as from the noise of planes, firearms, or loud music). In rare situations, tinnitus may […]
- Ringworm (tinea)
Ringworm is a fungal infection of the skin previously thought to be due to a parasite (worm). The medical term for ringworm is tinea. The skin infections are sometimes characterized by round lesions in the upper layers of the skin. Fungi that cause ringworm are known as dermatophytes.