Dictionary

ointment An oil-based preparation that is applied to the skin. Whereas an ointment has an oil base, a cream is water soluble.

olecranon The bony tip of the elbow. The olecranon is the near end of the ulna, the bone in the forearm, and it forms the pointed portion of the elbow. The triceps muscle tendon of the back of the arm attaches to the olecranon. Disease can affect the olecranon. For example, inflammation of the tiny…

olfaction The sense of smell.

olfactory apparatus The whole system that is needed to have a sense of smell, including the nose and affiliated nerves.

olfactory nerve The nerve that carries impulses for the sense of smell from the nose to the brain. The olfactory nerve is the first cranial nerve.

oligo- Prefix meaning just a few, or scanty, as in oligodactyly (having fewer than 10 fingers or 10 toes) and oliguria (less urination than normal).

oligodactyly Having fewer than the normal number of fingers or toes. Oligodactyly is the opposite of polydactyly.

oligodendrocyte A type of cell in the central nervous system. The oligodendrocytes surround and insulate the long fibers (axons) through which the nerves send electrical messages.

obesity-related disease A disease for which obesity is a significant risk factor. Obesity increases the risk of developing a number of diseases, and it can be a diagnostic marker for others. Diseases related to obesity include type 2 diabetes; high blood pressure (hypertension); stroke (cerebrovascular accident); heart attack (myocardial infarction); heart failure (congestive heart failure);…

OB/GYN 1 Obstetrician/gynecologist. 2 Obstetrics and Gynecology

observer variation Failure by the observer in a study or test to measure accurately, resulting in error. Inter-observer variation is the amount of variation between the results obtained by two or more observers examining the same material. Intraobserver variation is the amount of variation one observer experiences when observing the same material more than once.

obsessive-compulsive disorder An anxiety disorder that is characterized by obsessive thoughts and compulsive actions. Abbreviated OCD. The obsessive thoughts are unwanted ideas or impulses that repeatedly well up in the mind of the person with OCD. These thoughts are intrusive and unpleasant, and they produce a high degree of anxiety. In response to their obsessions,…