THE ABDOMEti ?>Ii 



branch of the genito-crural nerve and the cremasteric branch of the deep 

 epigastric artery- are to be noted, and the cremasteric fascia is to be studied. 



The internal oblique is to be removed in the following manner : make an 

 incision carefully through the muscle just in front of the anterior superior 

 iliac spine, and expose the lateral or intermuscular epigastric branch (so-called 

 ascending branch) of the deep circumflex iliac artery. This is the best guide 

 to the separation between the internal oblique and transversalis abdominis. 

 Now carry an incision inwards through the internal oblique towards the linea 

 alba, and leave the Poupart fibres undisturbed" in the meantime. The internal 

 oblique is next to be detached from the iliac crest, from the posterior aponeu- 

 rosis of the transversalis abdominis, and from the lower three or four costal 

 cartilages, and the muscle, with its aponeurosis, is to be thrown forwards as 

 far only as the outer border of the rectus abdominis. During the reflection 

 of the muscle care must be taken to preserve the following structures, 

 namely, the lower five intercostal nerves ; the anterior primary division 

 of the twelfth thoracic nerve (subcostal nerve) ; the hypogastric branch 

 of the ilio - hy-pogastric nerve ; the inguinal (so-called ilio-inguinal) nerve ; 

 the lateral or intermuscular epigastric artery ; the abdominal brajjches 

 of the lumbar arteiies ; and the lower two intercostal arteries. The 

 transversalis abdominis is next to be cleaned and studied. The lower five 

 intercostal nerves and the anterior primary division of the twelfth thoracic 

 nerve are to be followed forwards as far as the outer border of the rectus 

 abdominis, where they disappear by piercing the sheath to get behind the 

 muscle. The posterior aponeurosis of the muscle (which forms the lumbar 

 aponeurosis) cannot be displayed in the present position of the body, but the 

 anterior aponeurosis should be dissected as far as the outer border of the 

 rectus abdominis, where it will be further studied in connection with the 

 sheath of that muscle. 



The dissector should now direct his attention to the Poupart fibres of the 

 internal obhque and transversalis abdominis. He will find that the Poupart 

 fibres of the two muscles are intimately connected together, but a careful 

 dissection wiU show that, whilst the internal oblique arises from the outer 

 half of Poupart's ligament on its abdominal aspect, the transversalis abdominis 

 arises only from the outer third. The former muscle, then, reaches lower 

 down along Poupart's ligament than the latter. An incision having been 

 made through the transversalis abdominis in a transverse direction inwards 

 from the anterior superior iliac spine, the Poupart fibres of the two muscles 

 are to be detached from the ligament, and, in the course of reflecting them 

 inwards without injuring the fascia transversalis, the dissector should observe 

 their varying relations to the spermatic cord and internal abdominal ring, 

 and also the lower border of each muscle. These fibres of the two muscles 

 will be found to end in the conjoined tendon, and this structure should be 

 followed to its insertion and studied. It will be found that the anterior 

 aponeurosis of the transversalis abdominis contributes more to the con- 

 joined tendon than the aponeurosis of the internal oblique. The relation 

 of the conjoined tendon to Hesselbach's triangle will be presently seen. 

 Meanwhile the dissector is to observe that the tendon lies behind the sper- 

 matic cord (or round ligament of the uterus), and that it also lies behind 

 the external abdominal ring, thereby strengthening an otherwise weak part 

 of the abdominal wall. The dissector should look for the reflected tendon 

 of Cooper. If present, it will be found as a thin semilunar expansion, extending 

 outwards from the outer border of the conjoined tendon to the inner and 

 lower part of the internal abdominal ring, where it is attached to the deep 

 crural arch. Its relation to Hesselbach's triangle, as well as to the inguinal 

 canal, will be seen further on in the dissection. At this stage the dissector 

 of the abdomen should associate himself with the dissector of the lower limb 

 in order to make a dissection of the deep crural arch. 



The anterior wall of the sheath of the rectus abdominis is now to be opened 

 and reflected by making a vertical incision through it about an inch and a half 

 from the linea alba, and turning one half inwards and the other outwards, 

 preserving at the same time the transmitted nerves. In doing so the close 



