HYPERTROPHY ( from Gk. ir/p, hyper, over + rpooh, trophy'. nourishment, from ;pi-0m, trephein, to nourish). The term applied in medicine to the abnormal and di:proportion ate enlargement of any part of the body. Ex amples of this change are seen in the muscular system, where it may occur altogether indepen dently of disease. The huge bosses of flesh that stand prominently forward in the arm of a black smith or of a pugilist, and in the leg of a ballet dancer, are illustrations of hypertrophy from in creased use, where the general health may be perfect. Tn double organs, such as the kidneys and lungs. if the organ on one side degenerates through disease, the organ on the opposite side is often found to enlarge. and carry on double work. in these eases hypertrophy is an effect of disease, but is at the same time a preservative of life.
There are, however. eases in which the hyper trophy has a hurt fnl instead of a conservative effect, as. for example, hypertrophy of the thy
roid gland. constituting the disease known as goitre or bronchocele, hypertrophy of the prostate gland. of the spleen, etc. The following :ire the etiologieal factors Of hypertrophy: I I ) It may be congenital. (2) A local increase in the supply of blood to a part. whether due to increased ex or irritation by mechanical or chemical agents, etc. (3) It may be due to old age—the so-called senile hypertrophy. the communat ex ample of which is the enlargement of the prostate gland in old men, which is said to occur in about forty iler vent. of all men alter the age of fifty years. (4) Syphilis and chronic inflammations are also very common causes of hypertrophy. Ncc 11 EA HT, DISEASES OF T E.