910 A MANUAL OF ANATOMY 



dartos tunic to Camper's and Scarpa's fasciae of the anterior abdominal wall, 

 and to the two layers of the superficial fascia of the anterior division of the 

 perineum, is to be carefully noted. The testis is next to be withdrawn from 

 the scrotum, by making forcible traction upon the spermatic cord, and, when 

 this has been done upon both sides, a view wiU be obtained of the interior 

 of the scrotum. The dissector will notice that there are two scrotal chambers, 

 each lodging a testis, and separated from one another by a partition, known 

 as the septum scroti. The constituent parts of the scrotal wall and scrotal 

 septum are next to receive attention, and the blood-supply and nerve-supply 

 are to be fully reviewed. 



The dissector should now replace the testis in the scrotum, and return to 

 the dissection of the antero-lateral wall of the abdomen. The external 

 oblique is to be dissected and studied. In dissecting the posterior border of 

 the muscle its relation to the latissimus dorsi is to be noted. If it is not 

 overlapped by the last-named muscle, the interval between them, called the 

 triangle of Petit, is to be examined. The interdigitations with the latissimus 

 dorsi and serratus magnus are to be shown, and, in connection with the 

 external oblique aponeurosis, the intercolumnar fibres are to be displayed. 

 In the region of the external abdominal ring these fibres are to be shown 

 folding themselves around the spermatic cord in the form of the finger of a 

 glove, thus forming the intercolumnar or external spermatic fascia. The 

 attachment of this fascia along the pubic crest is to be noted, and, partly 

 on this account, and partly by reason of the attachment of the intercolumnar 

 fibres to the pillars of the external abdominal ring, it will be evident that 

 extravasated urine, in passing upwards along the spermatic cord, cannot 

 enter the inguinal canal. The following parts of the external oblique aponeu- 

 rosis require special attention : Poupart's ligament ; Gimbernat's ligament ; 

 the triangular fascia or ligament of CoUes, which will be found lying within 

 the external abdominal ring behind the spermatic cord and internal pillar ; 

 the external abdominal ring ; and the linea alba. In connection with the 

 external abdominal ring, its condition is to be carefully studied (i) in its 

 natural state, (2) after partial dissection, a circular cut having been made 

 in the intercolumnar fascia at the mouth of the ring, and (3) after complete 

 dissection, the intercolumnar fibres having been completely removed. The 

 following structures should be observed through the ring, namely, the 

 triangular fascia or ligam«mt of Colles, and the conjoined tendon of the 

 internal oblique and transversalis abdominis. The position of the spermatic 

 cord as it passes through the ring is to be noted. 



The removal of the external oblique is to be effected in the following manner : 

 an incision is to be carried inwards through the aponeurosis from the anterior 

 superior iliac spine to the linea alba, and another is to be made vertically 

 downwards in the median line to the symphysis pubis. The triangular 

 flap of the aponeurosis so included, containing the external ring, is to be 

 turned downwards, and left intact, so that it can be replaced when studying 

 the inguinal region in connection with hernia. Beneath this portion of the 

 aponeurosis the dissector is to preserve the hypogastric branch of the ilio- 

 hypogastric nerve as far outwards as about an inch in front of the anterior 

 superior iliac spine. The external oblique is next to be detached from the 

 iliac crest and lower eight ribs, preserving the lateral cutaneous nerves, and 

 the muscle, with the remainder of its aponeurosis, is to be reflected as far^ 

 forwards as possible. At no point is it possible to reflect it quite up to the 

 linea alba, but it can be reflected more completely below the level of the 

 umbilicus than above it. The reason why the external oblique aponeurosijj 

 cannot be separately raised quite up to the linea alba will be seen to be because 

 it blends inseparably with the subjacent anterior lamina of the aponeurosis 

 of the internal oblique. This latter muscle is now to be cleaned, preserving 

 the hypogastric branch of the ilio-hypogastric nerve, and the lateral cutaneous 

 nerves, all of which pierce it. In cleaning the Poupart fibres of the muscle,| 

 the origin of the cremaster is to be brought into view. The complex relatiol 

 of the Poupart fibres to the spermatic cord is to receive attention, and the 

 cremaster is to be dissected. In connection with this muscle the genita' 



