Fractures implicating the pelvic girdle as a whole usually result from severe crushing forms of violence, such as the fall of a mass of coal or a pile of timber, or the passage of a heavy wheel over the pelvis. The force may act in the transverse axis of the pelvis, or in its antero-posterior axis. The pelvic viscera may be lacerated by the tearing asunder of the bones, or perforated by sharp fragments, or they may be ruptured by the same violence as that causing the fracture.
As a rule, more than one part of the pelvis is broken, the situation of the lesions varying in different cases.
Separation of the pubic symphysis may result from violence inflicted on the fork, as in coming down forcibly on the pommel of a saddle; from forcible abduction of the thighs; or it may happen during child-birth. In some cases the two pubic bones at once come into apposition again, and there is no permanent displacement, the only evidence of the injury being localised pain in the region of the symphysis elicited on making pressure over any part of the pelvis. In other cases the pubic bones overlap one another, and the membranous portion of the urethra, or the bladder wall, is liable to be torn. The displaced bones may be palpated through the skin, or by vaginal or rectal examination.
The pubic portion of the pelvic ring is the most common seat of fracture. The bone gives way at its weakest points—namely, through the superior (horizontal) ramus of the pubes just in front of the ilio-pectineal eminence, and at the lower part of the inferior (descending) ramus ([Fig. 55]). The intervening fragment of bone is isolated, and may be displaced. These fractures are frequently bilateral, and are often associated with separation of the sacro-iliac joint, with longitudinal fracture of the sacrum ([Fig. 55]), or with other fractures of the pelvic-bones.
Fig. 55.—Multiple Fracture of Pelvis through Horizontal and Descending Rami of both Pubes, and Longitudinal Fracture of left side of Sacrum.
Injuries of the membranous urethra and bladder are frequent complications, less commonly the rectum, the vagina, or the iliac blood vessels are damaged.
Localised tenderness at the seat of fracture, pain referred to that point on pressing together or separating the iliac crests, and mobility of the fragments with crepitus, are usually present. The fragments may sometimes be felt on rectal or vaginal examination. In all cases shock is a prominent feature.
The lateral and posterior aspects of the pelvic ring may be implicated either in association with pubic fractures or independently. Thus a fracture of the iliac bone may run into the greater sciatic notch; or a vertical fracture of the sacrum or separation of the sacro-iliac joint may break the continuity of the pelvic brim. In rare cases these injuries are accompanied by damage to the intestine, the rectum, the sacral nerves, or the iliac blood vessels.