Dictionary

AV node Atrioventricular node.

avascular necrosis A condition in which poor blood supply to an area of bone leads to bone death. Abbreviated AVN. Also known as aseptic necrosis and osteonecrosis.

avian influenza A highly contagious viral disease with up to 100 percent mortality in domestic fowl. Caused by influenza A virus subtypes H5 and H7. All types of birds are susceptible to the virus, but outbreaks occur most often in chickens and turkeys. The infection may be brought by migratory wild birds which can carry…

AVM Arteriovenous malformation. See malformation, arteriovenous.

avulsion Tearing away. A nerve can be avulsed by an injury, as can part of a bone.

axilla Armpit.

axillary Pertaining to the armpit, the cavity beneath the junction of the arm and the body.

axillary dissection Removal of a portion of the lymph nodes under the arm.

axis The second cervical vertebra. The first cervical vertebra (atlas) rotates around the odontoid process of the axis. See also atlas; atlantoaxial joint.

axon A long fiber of a nerve cell (neuron) that acts somewhat like a fiber-optic cable to carry outgoing messages. The neuron sends electrical impulses from its cell body through the axon to target cells. Each nerve cell has one axon. An axon can be over a foot in length. See also dendrite; neuron.

Ayurveda India’s traditional, natural system of medicine that has been practiced for more than 5,000 years. Ayurveda provides an integrated approach to preventing and treating illness through lifestyle interventions and natural therapies. Ayurvedic theory states that all disease begins with an imbalance or stress in the individual’s consciousness. Lifestyle intervention is a major ayurvedic preventive…

azotemia A higher-than-normal blood level of urea or other nitrogen-containing compounds. The hallmark test for azotemia is the serum blood urea nitrogen (BUN) level. Azotemia is usually caused by the inability of the kidneys to excrete these compounds.