338 SURGICAL APPLIED ANATOMY. [Chap. xvm. 



at about the twenty-fourth year. In one case the an- 

 terior inferior spinous process was torn off by the rectus 

 muscle during the act of running a race. The os 

 innominatum has been broken into its three anatomical 

 portions. This accident cannot take place after about 

 the seventeenth year, since by that time the Y-shaped 

 cartilage is usually fully ossified, and the three 

 elementary bones are firmly united. Before such 

 consolidation occurs abscess in the hip joint not very 

 infrequently makes its way through the cartilage into 

 the pelvis. The acetabulum has been fractured, and 

 the head of the femur driven through its thinnest part 

 into the pelvis. In fractures of the pubes and 

 ischium the bladder has been torn by the sharp 

 fragments. In one case a loose piece of boiio that 

 had been driven into the bladder became the nucleus 

 for a stone. The urethra and vagina also have been 

 lacerated, or seriously compressed by the displaced 

 bones. In fractures of the sacrum the rectum has 

 been torn, or has been so compressed by the lower 

 fragment (which is almost always carried forwards) 

 as to be nearly closed. 



Special parts of tlie pelvis. Symphysis. 

 Separation of the bones at the symphysis without 

 fracture has occurred from severe violence. Malgaigne 

 reports three cases where the separation was brought 

 about by muscular violence only, by extreme action 

 of the adductor muscles of the two sides. The 

 Sigaultean operation consisted in dividing the sym- 

 physis pubis in cases of contracted pelvis, with the 

 idea of obtaining more room during labour, and of so 

 avoiding Caesarian section* It has been shown, how- 

 ever, that to gain half an inch in the antero-posterior 

 diameter the bones must be separated to the extent of 

 two inches. Such a separation involves laceration of 

 the sacro-iliac ligaments, and more or less damage to 

 the attachments of the pelvic viscera. 



