ABDOMINAL WALL 393 



these loops descend varies. Some reach the tunica vaginalis 

 of the testicle, and the scrotum should now be opened up, on 

 the right side, in order that they may be traced downwards 

 to this point; the majority of the fibres, however, do not 

 reach so far down, some going no farther than the sub- 

 cutaneous inguinal ring. Upon the posterior aspect of the 

 cord the loops are directed upwards, and some, reaching the 

 os pubis, obtain a tendinous insertion into its tubercle and 

 crest. 



It will be noticed that the cremasteric fleshy loops do not 

 form a complete investment for the cord and testis. The 

 intervals between the fasciculi are occupied by areolar tissue, 

 and this combination of muscular and areolar tissue is some- 

 times termed the cremasteric fascia. 



Reflection of Internal Oblique. On the right side of the body the 

 entire muscle may be reflected, but on the left side preserve the lower 

 portion of it (i.e. that part which is still covered by the aponeurosis of 

 the external oblique) in situ. Begin below by dividing the muscular fibres 

 along the crest of the ilium. The depth to which the knife should be 

 carried is indicated by the dense areolar tissue which lies between the internal 

 oblique and the subjacent transverse muscle. An ascending branch from the 

 deep circumflex iliac artery will also serve as a guide. This vessel emerges 

 from the fibres of the transverse muscle, close to the fore-part of the iliac 

 crest, and is then directed upwards upon its surface. Although this vessel 

 has not attained the dignity of a name, it is a very constant branch. On 

 the right side the fibres springing from the inguinal ligament should also be 

 severed, but on the left side carry the knife horizontally, from the anterior 

 superior spine of the ilium to the lateral margin of the rectus. Now 

 turn to the upper part of the muscle, and make an incision through it 

 along the lower margin of the thorax, from the lateral border of the rectus 

 to the last rib. Lastly, carry the knife downwards, from the tip of the last 

 rib to the crest of the ilium. 



The muscle freed in this manner can be thrown medially towards the 

 lateral border of the rectus. In doing this the dissector must proceed with 

 caution, because he has reached the plane of the main trunks of the nerves 

 of the abdominal wall and the arteries which accompany them. These 

 pass medially between the internal oblique and transverse muscle, and, as 

 the former muscle is raised, they are apt to adhere to its deep surface and 

 be cut. 



In all probability the student will experience considerable difficulty in 

 separating the lowest part of the internal oblique from the corresponding 

 portion of the transversus abdominis. At this level these two muscles are 

 always closely connected, and in some cases they may be even found to be 

 partially blended. 



The cremaster muscle should also be reflected from the spermatic cord. 

 This can best be done by making a longitudinal incision along it. Entering 

 the deep surface of the cremaster is a small branch of the inferior epigastric 

 artery and the external spermatic nerve (a branch of the genito-femoral}. 

 These constitute its vascular and nervous supply, and must, if possible, be 

 secured. Now clean the transversus abdominis muscle, and dissect out the 

 vessels and nerves which lie upon it. 



