THE ABDOMEN 92 1 



the preceding, and is readily recognised by crossing the iliac fossa to a point 

 beneath the outer end of Poupart's ligament, where it passes out to the 

 thigh. The anterior crural nerve will be found lying deeply in the groove 

 between the psoas magnus and iliacus, and the obturator nerve will be found 

 lying deeply on the inner side of the psoas magnus, on its way to the lateral 

 wall of the pelvis. If an accessory obturator nerve is present, it will usually 

 be found passing deeply along the inner side of the psoas magnus, close to the 

 peh'ic brim, and then coursing over the superior pubic ramus, where it passes 

 beneath the pectineus. 



The psoas magnus is now to be dissected, and a psoas parvus is to be 

 looked for. The nerves are tlien to be followed upwards and inwards to their 

 origins, by cutting through the psoas magnus. In this manner the lumbar 

 plexus will be exposed, which should be carefully dissected, the lumbo-sacral 

 cord being shown, at the same time, descending to take part in the sacral 

 plexus. The gangliated cord of the sympathetic is to be displayed in front 

 of the bodies of the lumbar vertebrae, and the length of its rami communi- 

 cantes, which accompany the lumbar arteries, is to be noted. The lumbar 

 branches of the aorta are now to be dissected as far back as the intervals 

 between the lumbar transverse processes, where the lateral lumbar glands 

 should be looked for. If the lumbar veins have not been previously dissected, 

 this should now be done. In connection with these veins, at either side, the 

 ascending lumbar vein is to be shown, that of the right side ending as the right 

 azygos vein, and that of the left side ending as the lower left azygos vein. 

 The posterior aponeurosis of the transversahs abdominis and the quadratus 

 lumborum are next to be dissected, and, if that muscle is cut, it will be seen 

 to be encased in a sheath which is formed by the anterior and middle laminae 

 of the aponeurosis. The iliacus muscle and the external iliac vessels are 

 now to be dissected, and the relation of the vessels to the peritoneum, sub- 

 peritoneal tissue, and iliac fascia is to be carefuUy noted, as well as their 

 relation to the genito-crural nerve and constituents of the spermatic cord. 

 The principal branches of the artery, namely, the deep epigastric and deep 

 circumflex iliac, are to be shown, and related to the artery will be found the 

 external iUac glands, three of them being placed just above Poupart's liga- 

 ment, one on the outer side, another on the inner side, and a third in front 

 of the vessel. The deep circumflex iUac artery' is to be followed behind the 

 outer half of Poupart's ligament, and along the iliac crest, and its anastomoses 

 are to be studied. The lacunar region, which lies between Poupart's liga- 

 ment and the front of the hip-bone, is to be examined, and its two muscular 

 lacunae, outer and inner, A^ath the vascular lacuna in front of them, are to be 

 sliown, with the structures lying in each. 



Pelvis. 



The pelvis is to be separated by cutting through the disc between the third 

 and fourth lumbar bodies, and then applying the saw. The various muscles 

 connected with the exterior having been trimmed, the bladder is to be partially 

 inflated, and the general position of the viscera and their relations are to be 

 studied, as far as possible, in situ. The extent of the pelvic colon is to be noted, 

 and its extensive mesentery, with the superior hemorrhoidal vessels between 

 its two layers, observed. 



The reflections of the peritoneum are then to be examined. If a male 

 subject, the relation of the peritoneum to the bladder is to be thoroughly 

 mastered, and the false ligaments, which it forms for the viscus, noted. The 

 recto-vesical pouch of the peritoneum is also to be observed. If a female 

 subject, the relation of the peritoneum to the uterus is to be studied, and 

 the recto-uterine pouch, or pouch of Douglas, is to be carefully examined, 

 which usually contains a few coils of the ileum, and, it may be, a prolapsed 

 ovary. The broad ligament of the uterus, formed by two layers of peri- 

 toneum, is to be studied. The position of the Fallopian tube along its upper 

 border, of the ovary with its ligament in a backward extension of it, and of the 

 round ligament of the uterus in a forward extension of it, are to be observed. 



