Anterior: The front, as opposed to the posterior. The anterior surface of the heart is toward the breast bone (the sternum).
For a more complete listing of terms used in medicine for spatial orientation, please see the entry to “Anatomic Orientation Terms”.
- Anterior chamber
Anterior chamber: The space in the eye that is behind the cornea and in front of the iris. The cornea is the outer, transparent, dome-like structure that covers the iris, pupil, and the anterior chamber. The iris is the colored ring of tissue suspended behind the cornea and immediately in front of the lens; it […]
- Anterior cruciate injury
Anterior cruciate injury: A knee injury involving the anterior cruciate ligament (ACL). The ACL runs diagonally deep inside the knee from the center of rotation of the end of the femur (the thigh bone) to the top of the tibia (the larger bone in the lower leg). Females are seven times more likely to suffer […]
- Anterior cruciate ligament
Anterior cruciate ligament: A ligament in the knee that crosses from the underside of the femur (the thigh bone) to the top of the tibia (the bigger bone in the lower leg). Abbreviated ACL. Injuries to the ACL can occur in a number of situations, including sports, and can be quite serious, requiring surgery. The […]
- Anterior pituitary
Anterior pituitary: The front portion of the pituitary, a small gland in the head called the master gland. Hormones secreted by the anterior pituitary influence growth, sexual development, skin pigmentation, thyroid function, and adrenocortical function. These influences are exerted through the effects of pituitary hormones on other endocrine glands except for growth hormone which acts […]
- Anterior tongue
Anterior tongue: The front two-thirds of the tongue. In contrast to the base of the tongue, which is the back third. The distinction between the anterior and base of the tongue reflects the fact that they are of different embryological origin. The distinction also matters as regards cancer. See: Tongue cancer.