204 INTRA-PEL VIC AMPUTA TION. 



incision sufficiently to admit the operator's hand into the 

 fetal pelvis. Locate the great sciatic ligament and inserting 

 the knife at the shaft of the ilium divide the former back- 

 ward to the perinaeum allowing the pelvic cavity to dilate 

 freely and giving ample operating room. If the pelvis of the 

 fetus is too small to admit the hand of the operator at all be- 

 fore severing the sciatic ligament this may be accomplished 

 by cautiously cutting from behind forward with Colin 's 

 scalpel or with the chisel. When this has been severed and 

 sufficient operating room attained carry the chisel with one 

 hand and plctce it against the shaft of the ilium as shown 

 between I' I' in Plate XXXIII as nearly perpendicular to 

 the long axis of the shaft as possible and keeping the hand 

 in touch with the chisel blade have an assistant drive it 

 through the bone until it and its periosteum are completely 

 severed. Disengage the chisel and then place it against the 

 symphysis pubis or against theischium opposite the foramen 

 ovale and drive it through the ischium and pubis at this 

 point. Using the chisel as a lever, separate the isolated por- 

 tion of the pelvis as completely as practicable from the sur- 

 rounding tissues, and with the ringers separate the muscles 

 from the detached pelvic bone for a short distance on 

 either side from the severed ends. Carry a cord in and 

 pass the loop over the ends of the severed section and 

 tightening it secure the isolated portion of the pelvis and 

 have one or more assistants exert traction upon the cord 

 as indicated in Plate XXXIV. The chief obstacle to the 

 withdrawal of the limb is the great glutens muscle which 

 should be sought for, identified and torn through with the 

 ringers at a distance of 5 or 6 cm. from its attachment to the 

 great trochanter. Other important points of resistance are 

 the attachment posteriorly of the skin, vulva and anus to 

 the ischium through the medium of aponeurosis and anter- 

 iorly, chiefly on the median line, the prepubic tendon ; these 

 are to be cut, if necessary, with the chisel or knife. Vigor- 



