248 THE ABDOMEN AND PELVIS 



tend to leave a weakness in the anterior abdominal wall when 

 they heal. This is due to the normally existing interval between 

 the upper portions of the two recti muscles, and maybe prevented 

 in the following way. A vertical incision, the length of the 

 original wound, is made through the anterior wall of each rectus 

 sheath along its medial border, and the medial edges of these 

 cuts are stitched together (Fig. 75) by sutures which also pass 

 through the peritoneum. In this way the gap is bridged by 

 strong tissue which is not too tightly stretched. The medial 

 edges of the recti and the anterior layers of their sheaths are 

 stitched together over the newly-formed deep layer of the 

 abdominal wall (Stiles). 



The same method may be adopted in the radical cure of a 

 ventral hernia in this region. 



The "Gridiron Incision" is planned so as to minimise, 

 as far as possible, the subsequent weakness in the abdominal 

 wall. The fibres of the various muscles are not cut across but 

 are separated in the direction in which they run. It is most 

 frequently employed in inguinal colotomy and in the oblique ap- 

 proach to the vermiform process (appendix) over M'Burney's point 

 (which lies at the junction of the middle and lower thirds of the 

 line joining the umbilicus to the anterior superior iliac spine). 



The skin and fascia are divided downwards and medially, 

 exposing the glistening aponeurosis of the external oblique, 

 and in the upper part of the wound some of its muscular fibres. 

 The aponeurosis is split in the line of the incision, i.e. parallel 

 to the direction of the muscular fibres, and the split is continued 

 upwards into the fleshy part of the muscle. When the cut 

 edges are retracted, the lower part of the internal oblique is 

 exposed. In this region the fibres of both the internal oblique 

 and the transversus abdominis (transversalis) are practically 

 horizontal, but in the lower part of the wound they turn 

 downwards to form the falx inguinalis (conjoined tendon). These 

 two parts of both muscles are separated from one another along 

 a horizontal line at the level of the anterior superior spine. The 

 fascia transversalis, which is now exposed, and the underlying 

 peritoneum are opened at the same time, but great care must 

 be exercised, as the bowel may be adherent to the latter. 



If the muscular interval, obtained in this way, does not give 

 sufficient access, the split may be extended both laterally and 

 medially. In the former direction it may be carried to the 

 anterior superior spine, exposing the ascending branch of the 



