Abdominal muscles: A large group of muscles in the front of the abdomen that assists in the regular breathing movement and supports the muscles of the spine while lifting and keeping abdominal organs such as the intestines in place. Abdominal muscles play a key role in exercises such as “sit-ups.” They are informally called the “abs”.
Abiotic: 1. Not associated with living organisms. 2. Anything in the environment incapable of life, such as the soil or weather. 3. Incompatible with life or antagonist to it. Also called abiological.
- Abducent nerve
Abducent nerve: The sixth cranial nerve, which emerges from the skull to operate the lateral rectus muscle. This muscle draws the eye toward the side of the head. Paralysis of the abducent nerve causes inward turning of the eye.
Ablation: Removal or excision. Ablation is usually carried out surgically. For example, surgical removal of the thyroid gland (a total thyroidectomy) is ablation of the thyroid.
- ABG (arterial blood gas)
ABG (arterial blood gas): The sampling of the blood levels of oxygen and carbon dioxide within the arteries, as opposed to the levels of oxygen and carbon dioxide in venous blood. Typically, the acidity, or pH, of the blood is measured simultaneously in ABG sampling.
Abnormal: Outside the expected norm, or uncharacteristic of a particular patient.