Page:Structure and functions of the body; a hand-book of anatomy and physiology for nurses and others desiring a practical knowledge of the subject (IA structurefunctio00fiskrich).pdf/170

 take part of the weight from the abdominal walls, while the true pelvis, being more surrounded by bone and so capable of affording more protection, guards the internal organs of generation. The lower circumference of the pelvis is known as the outlet. In the female the bones are lighter, the sacrum less curved, and the diameters greater than in the male.

On the whole, the pelvic bones are well covered in with muscles. The anterior superior spine, however, is easily felt in front and the whole crest can be felt back to the posterior superior spine. The tuberosity of the ischium also can be felt, especially when the thigh is flexed, for it is largely uncovered of muscles. The spine of the os pubis can always be felt, on a level with the great trochanter, and the relation of its position to that of a hernia shows whether the rupture is above or below Poupart's ligament, that is, whether it is inguinal or femoral.

Occasionally there is lack of development of the pubic bones for two or three inches and the bladder is exposed. Fracture of the pelvis may occur, perhaps with injury to the viscera. The acetabulum may be fractured or the sacrum broken, with injury to the sacral plexus of nerves, causing paralysis of the lower extremities and of the sphincters, with resultant involuntary passage of urine and feces, and in childbirth the coccyx is often broken. In rickets there may be great deformity of the pelvis, causing trouble in childbirth later in life. Osteomalacia is a disease of adults, in which the bones are soft and the weight pushes the promontory of the sacrum forward and approximates the sides of the pelvis.

The Male Generative Organs.—The male generative organs consist of the prostate gland, testes, and penis.

The prostate gland is shaped like a small horse-chestnut and is composed of numerous glands from which come a dozen or more excretory ducts. It surrounds the neck of the bladder and the beginning of the urethra