THE ABDOMINAL WALL 211 



seventh serrations carry an incision downwards, through the 

 fibres of the muscle, to the posterior border of the tubercle on 

 the external lip of the iliac crest. Raise the anterior portion of 

 the muscle from the surface of the subjacent internal oblique 

 and turn it medially, dividing the fleshy fibres inserted into the 

 iliac crest close to the bone. Next, divide the aponeurosis 

 horizontally, in a line leading from the anterior superior spine to 

 the lateral border of the rectus. The greater part of the muscular 

 and aponeurotic portion of the external oblique can now be 

 thrown medially. The dissector must proceed with care on 

 approaching the later.al border of the rectus, because a little 

 beyond that border the anterior lamella of the aponeurosis of the 

 internal oblique fuses with the deep surface of the aponeurosis 

 of the external oblique. Define the line of union, and notice 

 that it does not extend beyond the lower margin of the thorax. 

 Above that the rectus is covered merely by the aponeurosis of 

 the external oblique ; its lateral margin in that locality is bare, 

 and the hand can be freely passed between the rectus muscle 

 and the costal cartilages. 



On the left side of the body, the parts below the horizontal 

 line drawn from the anterior superior iliac spine to the lateral 

 border of the rectus, along which the aponeurosis of the external 

 oblique muscle has been divided, should be preserved intact for 

 the special study of the structures associated with inguinal hernia. 

 On the right side of the body, divide the lower part of the aponeu- 

 rosis along the lateral border of the rectus down to the pubis. 

 The incision should pass to the medial side of the superior crus 

 of the subcutaneous inguinal ring, so that that opening may be 

 preserved. The triangular flap of aponeurosis must now be 

 thrown downwards and laterally. By this proceeding the 

 inguinal ligament, the internal oblique muscle and the cremaster 

 muscle are displayed for study. 



Ligamentum Inguinale (Pouparti). The inguinal ligament 

 is merely the thickened lower border of the aponeurosis of the 

 external oblique folded backwards upon itself. It thus 

 presents a rounded surface towards the thigh and a grooved 

 surface towards the abdomen. The manner in which it is 

 attached by its lateral and medial extremities deserves the close 

 study of the dissector. Laterally it is fixed to the anterior 

 superior spine of the ilium ; medially it has a double attach- 

 ment, viz. (i) to the pubic tubercle, which may be con- 

 sidered as its attachment proper; (2) through the medium of 

 the lacunar ligament (Gimbernafs) to the ilio-pectineal line. 



The inguinal ligament does not pursue a straight course 

 between its iliac and pubic attachments. It describes a 

 curve, the convexity of which is directed downwards and 

 laterally towards the thigh. By its inferior border it gives 

 attachment to the fascia lata. When that is divided, the 

 inguinal ligament at once loses its curved direction, 

 nll a 



