THE ABDOMEN 913 



The next stage of the dissection consists in (i) detaching the transversalis 

 abdominis from the iliac crest, (2) cutting through posterior aponeurosis 

 in the region between the ihac crest and the last rib, and (3) dividing the 

 muscle as it escapes from beneath the costal margin. Wten the muscle has 

 been reflected forwards to the outer border of the rectus, the various nerves 

 on its surface having been divided in front and turned outwards, and the 

 ilio-hypogastric and inguinal nerves being carefully preserved in the region 

 of the iliac crest, a good view will be obtained of the fascia transversalis. 

 Before proceeding to study this fascia, however, it will well repay the dis- 

 sector to .replace for a moment the external oblique, internal oblique, and 

 transversalis abdominis, in order to show the intricate piece of lattice-work 

 which these muscles construct by the var5nng direction of their fibres, a cir- 

 cumstance which adds materiaJly to the strength of the abdominal wall. 

 The fascia transversahs should be followed upwards beneath the costal margin, 

 where, now very thin, it becomes continuous with the areolar investment of 

 the diaphragm. Towards the lower part of the abdominal wall it becomes 

 better marked. Its disposition along the Unea alba and along the iliac crest 

 is to be studied ; its arrangement along the line of Poupart's ligament should 

 be carefully attended to ; the deep crural arch is to be revised in connection 

 with it ; its relation to Hesselbach's triangle is to be noted ; and the internal 

 abdominal ring, with the infundibuliform fascia prolonged from its margins, 

 is to receive the closest attention. To see the ring the spermatic cord 

 (or round ligament of the uterus) should be puUed upon, and a circular 

 incision made through the infundibuliform fascia close to the ring. In 

 performing this dissection, it will be seen that the infundibuliform fciscia 

 is prolonged upon the cord as the internal spermatic fascia. If the cord 

 be pulled upon it will be seen to receive a covering from the sub- 

 peritoneal fat or areolar tissue through the internal ring. The internal 

 abdominal ring in all its bearings is to be fully studied, and the relation of the 

 deep epigastric vessels to it carefully noted. At this stage the deep circumflex 

 iliac artery should be dissected in the first part of its course. It will be found 

 in a canal behind the outer half of Poupart's ligament formed by the meeting 

 of the fascia transversalis and fascia iUaca, but it should not be dissected at 

 this stage beyond the anterior superior iliac spine, in which region it will be 

 found to pierce the fascia transversalis. 



The inguinal canal is next to be attended to, and its boundaries and relations 

 studied. The spermatic cord, or round ligament of the uterus, according to 

 the sex, is to be observed traversing it throughout, and the inguinal nerve 

 will be found in the lower two-thirds of the canal, after which it wUl be seen to 

 emerge through the external abdominal ring external to the spermatic cord. 

 Hesselbach's triangle should be revised at this stage, and the relation of the 

 conjoined tendon to the inguinal canal is to be noted. Further, if the reflected 

 tendon of Cooper should be present, its relation to the canal is to be observed. 

 The spermatic cord is next to be dissected. Lying in front of its upper part for 

 a variable distance may be found a thread-like prolongation of the peritoneum. 

 The various coverings of the cord are to be studied, and the dissector is to 

 note that there are three sj>ermatic fasciae. By teasing and separation the 

 various constituents of the cord are to be shown. Certain of these will not 

 be easily made out, such as the spermatic plexus of nerves and the lym- 

 phatics of the testis, but the vas deferens can be separated without difficidty. 

 The spermatic artery (in the centre of the cord), the pampiniform plexus of 

 veins, and the deferential artery are to be looked for. The round Ugament 

 of the uterus (a very variable structure in this part of its course) requires 

 very Uttle dissection, and may be followed into the labium majus. A few 

 fibres, representing the cremaister muscle in the male, should be looked for in 

 front of the round ligament. The fascia transversahs is now to be removed 

 as carefully as possible, and in doing so the dissector should observe that it is 

 connected to the underK-ing peritoneum by the subperitoneal fat or areolar 

 tissue. In connection with this tissue two points have to be noted, namely, 

 (i) internal to the external ihac vein it forms the septum crurale, closing 

 the crural or femoral ring, which should be studied in conjunction with the 



