Dictionary

adenocarcinoma A cancer that develops in the lining or inner surface of an organ and usually has glandular (secretory) properties. More than 95 percent of prostate cancers are adenocarcinomas.

adenitis Inflammation of a gland.

adenine A nucleotide member of the base pair adenine-thymine (A-T) in DNA.

adduction Movement of a limb toward the midline of the body. The opposite of adduction is abduction.

adducted thumbs Clasped thumbs, caused by absence of the extensor pollicis longus and/or brevis muscles to the thumb. When associated with mental retardation, it is part of an X-linked syndrome that affects mainly boys. See MASA syndrome.

Addison’s disease Chronic underfunction of the outer portion of the adrenal gland, most commonly due to autoimmune destruction. Other causes include physical trauma to the adrenal gland, hemorrhage, tuberculosis, and destruction of the pituitary gland cells that secrete adrenocorticotropic hormone (ACTH), which normally controls the adrenal gland. Addison’s disease is characterized by bronzing of the…

Addison’s anemia See anemia, pernicious.

addiction An uncontrollable craving, seeking, and use of a substance such as alcohol or another drug. Dependence is such an issue with addiction that stopping is very difficult and causes severe physical and mental reactions.

ADD 1 Attention deficit disorder. 2 Adenosine deaminase deficiency.

Adam’s apple The familiar feature on the front of the neck that is the forward protrusion of the thyroid cartilage, the largest cartilage of the larynx. It tends to enlarge at adolescence, particularly in males. It is usually said to take its name from the extrabiblical story that a piece of the forbidden fruit stuck…

ADA 1 American Dental Association, a professional organization for dentists. Its Council on Dental Education and Commission on Dental Accreditation are responsible for accrediting schools of dentistry and allied professions. 2 American Diabetes Association, a nonprofit health organization that sponsors diabetes research, provides information about diabetes and diabetes prevention to patients and others, and advocates…

ad lib Abbreviation of the Latin phrase ad libitum, meaning “as much as one desires” or “at your discretion.” See also Appendix A, “Prescription Abbreviations.”