Dictionary

atonic Without normal muscle tone or strength. An atonic seizure is one in which the person suddenly loses muscle tone and strength; the person cannot sit or stand upright and, unless supported, falls down.

atlas The first vertebra in the neck. It supports the head at the base of the skull. Also known as first cervical vertebra.

atlantoaxial joint The joint between the first (atlas) and second (axis) vertebrae of the neck beneath the skull. The axis features a bony prominence called the odontoid process, about which the atlas rotates. The atlantoaxial joint is a pivot type of joint. It allows the head to turn from side to side. The atlantoaxial joint…

athlete’s foot A skin infection caused by a fungus called Trichophyton that thrives within the upper layer of the skin when it is moist, warm, and irritated. The fungus can be found on floors and in socks and clothing, and it can be spread from person to person through contact with these objects. However, without…

athetosis Involuntary writhing movements, particularly of the arms and hands. Athetosis is associated with several neurological disorders, such as cerebral palsy and Rett syndrome.

atherosclerotic Pertaining to atherosclerosis. Atherosclerotic heart disease is the leading cause of death in the US. See atherosclerosis.

atherosclerosis The presence of fatty lipid deposits in the lining (intima) of an artery. Atherosclerosis is a form of arteriosclerosis. See also arteriosclerosis.

atheroma A fatty deposit in the inner lining (intima) of an artery, resulting from atherosclerosis. Also called an atherosclerotic plaque, an arterial plaque, or a plaque.

atherectomy A procedure to remove plaque (atheroma) from the inside of a blood vessel. Atherectomy is done most often in major arteries, such as the coronary, carotid, and vertebral arteries, that have experienced the occlusive effects of atherosclerosis. Atherectomy may be accomplished by various means, including angioplasty, laser surgery, conventional surgical incision, or use of…

1. Definition Athelia is the congenital or acquired absence of one or both nipples. It is a rare condition often associated with genetic syndromes or developmental abnormalities. 2. Causes and Associations 3. Related Conditions 4. Diagnosis and Management

atelectasis, secondary Partial or complete collapse of a previously expanded lung. Secondary atelectasis may occur when full chest expansion is difficult, such as after chest surgery.

atelectasis, primary Failure of full expansion of the lung at birth.