236 Anatomy Applied to Medicine and Surgery. 



the iliac spine. In the former case, an incision is made 

 parallel with and half an inch to the right of the edge of 

 the rectus. In the latter, the incision starts about half an 

 inch above the level of a line drawn from the anterior iliac 

 spine to the umbilicus, and at a distance of about one and 

 a half inches from that spine. The direction of this incision 

 is downwards and inwards and corresponds to the course 

 of the fibres of the external oblique, and on the separa- 

 tion of these fibres, the internal oblique and transversalis 

 muscles are divided in the line of the original incision. 

 The transversalis fascia, which is exposed on section of 

 the last named muscle, is incised and, lastly, the peri- 

 toneum is pinched up and opened between two pairs of 

 forceps, so as to avoid wounding any underlying bowel. 

 A serious objection to this method of operation, is the pos- 

 sibility of subsequent hernia developing at the site of the 

 abdominal wound, and to avoid this, McBurney has de- 

 vised the "gridiron" operation in which no muscular 

 structures are divided. The fibres of the internal oblique 

 and transversalis muscles are separated in the direction of 

 their fibres, and therefore, in a direction almost at right 

 angles to the superficial wound. The transversalis fascia 

 and the peritoneum are then incised, in the same direction 

 When, however, a tumor composed of the inflamed appen- 

 dix and adherent amentum or bowel, is palpable, the in- 

 cision may be made directly over it. In identifying the 

 appendix a reliable guide to it is the anterior longitudinal 

 band, since this, as well as the other longitudinal bands, 

 arose from the apex of the caecum in the foetus, and as 

 this apex becomes the appendix in the adult, these bands 

 still retain their relationship to the appendix, so that by 

 following down the longitudinal band it will be found to 

 lead to the base of the appendix. 



