FRACTURES OF THE RING.—Under this title are grouped all fractures that dissolve the continuity of the pelvic ring. Such fractures must, of necessity, be ver tical in the main. They are usually caused by a crushing from before back ward. The line of fracture usually runs through the upper (just internal to the pectineal eminence) and lower (near its junction to the ischium) rami of the pubic bone. Such a fracture may be bilateral, and associated with a vertical fracture of the sacrum, a separation of the sacro-iliac syncbondrosis, or a fract ure through the ilium behind the ace tabulum. These are the double vertical fractures of the pelvis. This double fracture may also occur from a fall on the foot, or the same cause may dislocate the os innominatum at both symphyses. Or it may cause a radiating fracture of the acetabulum with or without penetra tion of the femoral head through the bone. Fractures of the ring are usually
comminuted. Displacement of small fragments or a general mobility, with crepitus, of the whole pelvis may often be recognized. In double vertical fract ure the fractured bone is Often tilted; so that the superior strait is widened, the inferior strait narrowed, and the limb apparently shortened. Complications are usual and severe. Rupture of the membranous or prostatic urethra is al most inevitable, and the other common injuries are rupture of the pelvic vessels, the rectum, the bladder, and the ureters.
Treatment. — The associated injuries demand immediate attention. For the fracture itself rest in bed with even com pression all around the pelvis is all that can be done, except in cases of tilting of the os innominatum, in which traction should be made as after fracture of the thigh.