=The Pelvic Cavity.=—The pelvic cavity is that portion of the abdomen situated between the ilium and pubic bones, or in other words the extreme lowest portion of the abdominal cavity. The organs located within this cavity are the bladder in the male and the bladder and the uterus (womb) in the female. =The Bladder.=—The urinary bladder is a reservoir for the urine, situated in the pelvic cavity behind the pubic bone. In life it is supplied with blood by the anterior branches of the internal iliac arteries accompanied by the internal iliac veins. =The Uterus.=—The uterus is the organ of gestation, receiving the fecundated ovum into its cavity, retaining it, and supporting it during the development of the foetus, and becoming the principal agent in its expulsion at the time of parturition (delivery). It is nourished in life by branches of the internal iliac artery, which is accompanied by the iliac vein. The uterus is situated in the pelvic cavity between the rectum and the bladder, and is held in position by the lateral and round ligaments on each side. The uterus is about 3 inches in length, 2 inches in breadth and weighs from one to two ounces. It is composed of three coats, external serous, middle muscular, and internal mucous. The serous coat, derived from the peritoneum, is thin and vascular. The muscular coat is the chief coat, it is dense, firm, of a grayish color and cuts like cartilage. The mucous coat is thin, smooth and closely adherent to the muscular coat. It is highly vascular. The blood supply to the uterus is the uterine arteries which are the posterior branches of the internal iliac arteries, and the ovarian arteries which are branches of the aorta. These break up in capillaries and form a fine network plexus in the coats of the uterus. The veins are of large size and are the uterine which empty into the internal iliac veins and the ovarian veins. On the right side the ovarian vein empties into the ascending vena cava, and on the left side into the renal vein. =Prostate.=—The prostate gland is a pale, firm glandular body, which surrounds the neck of the bladder in the male. Its shape and size resembles a horse chestnut. It weighs from one-half to one ounce and measures one and one-half inches across and three quarters of an inch deep. Its structure is inclosed by a firm thin fibrous capsule. Its substance is of a pale reddish grey color and is composed of glandular substance and muscular tissue. The arteries that supply the prostate are derived from the internal pubic, a branch of the internal iliac. The veins form a plexus around the gland and communicate with veins which empty into the internal iliac veins. Its function is to secrete an opaque fluid. [Illustration: FIG. 27—The Peritoneum. (Gray)]