Atrophy

(at'-ro-fe). A retrogre ive change in parts originally well-formed and well-nourished, consisting in lo of weight, size, and function of an organ or ti ue, owing to some disorder of nutrition, disuse, continuous pre ure, or a diminished blood-supply to the part. A., Active, due to the inherent inability of the cells of a ti ue to a imilate the nutriment brought to them. A., Acute Yellow. See Icterus gravis. A., Brown, a form of atrophy in which the normal pigment of the organ is retained, and in which there is also frequently the addition of new pigment from the blood and disintegrated albuminates. It occurs most frequently in the heart, muscles, and liver, and is caused by chronic congestion; also called Pigmented Atrophy. A. of the Bulb, progre ive shrinking of the eyeball. A., Correlated, an atrophy of certain portions of the body following the removal or destruction of other portions. Thus amputation of an arm will be followed by an atrophy of the scapula; of a leg, of the corresponding os in nomina tum, together with a diminution in the size of the heart and large blood-ve els. A., Cruveilhier's. See Diseases, Table of. A., Gray, a degenerative change in the optic disc in which the latter a umes a grayish color. A. of Hair, a wasting or deficient growth of the hair. A., Idiopathic Muscular, primary muscular dystrophy; muscular wasting, with or without an initial hypertrophy, beginning in various groups of muscles, usually progre ive in character, and dependent on primary changes in the muscles themselves. There is a strong hereditary predisposition to the disease. A., Muscular, affects the muscles and may be hereditary or acquired, idiopathic, myelopathic, myopathic, neuropathic, primary, secondary, simple, or progre ive. A., Pa ive, caused by diminished nutrition supplied to the part. A., Pigmentary, so called from a deposit of pigment (yellow or yellowish brown) in the atrophied fat-cells. A., Pigmented. See A., Brown. A., Progre ive Muscular; Chronic Anterior Poliomyelitis; Wasting Palsy. A chronic disease characterized by progre ive wasting of individual muscles or physiologic groups of muscles, and by an a ociated and proportional amount of paralysis. It is due to a degeneration and atrophy of the multipolar cells in the anterior gray matter of the cord, with consecutive degeneration of the anterior nerve-roots and muscles.