THE ABDOMINAL WALL 251 



and the other just above the iliac crest. The transverse incisions 

 should commence at the median plane and should not extend 

 beyond the lateral margin of the mass of sacro-spinalis muscle. 

 The medial part of the divided fascia must be turned to the 

 median plane and its attachments to the tips of the spines 

 verified. The lateral part should be pulled laterally, and at the 

 lateral border of the mass of the sacro-spinalis it will be found to 

 blend with a deeper, middle, layer. Push the sacro-spinalis medi- 

 ally and follow the middle lamella to its attachment to the tips 

 of the transverse processes. The dissectors should then note that 

 the upper fibres of origin of the internal oblique spring from 

 the lumbar fascia just lateral to the line where the middle and 

 posterior lamellae of the fascia blend. There is still, however, 

 another lamella of the lumbar fascia the anterior lamella. To 

 display that part the dissector must divide the middle lamella 

 vertically, close to its attachments to the tips of the transverse 

 process, and transversely along the line of its attachment to the 

 iliac crest. The middle lamella can then be turned laterally, 

 and the posterior surface of the quadratus lumborum will be 

 brought into view. When the lateral border of the quadratus 

 lumborum muscle is displaced towards the median plane the 

 anterior lamella of the lumbar fascia will be exposed. The 

 dissector should place his finger upon its surface and trace it 

 medially and laterally. Medially he will be able to follow it to, 

 or to within a short distance of, the roots of the transverse 

 processes of the vertebrae, and laterally he will find that it joins 

 the remainder of the fascia some distance lateral to the union 

 of the posterior and middle lamellae. He must note, further, 

 that, beyond the union of the three lamellae, the lumbar fascia 

 is continued into the transversus abdominis, and thus it is, 

 through the lumbar fascia, that the transversus obtains its origin 

 from the tips of the spines and transverse processes, and from the 

 fronts of the transverse processes of the lumbar vertebrae. When 

 the dissector has satisfied himself regarding the lamellae of the 

 lumbar fascia and their relation to the internal oblique and the 

 transversus abdominis, he should carefully divide the anterior 

 lamella longitudinally, and, introducing his finger through the 

 incision, into the extra-peritoneal fatty tissue, he should scrape 

 away the latter until he exposes the lower part of the kidney, 

 below the level of the last rib ; and the adjacent part of the colon, 

 which lies along the lower and lateral part of the kidney. After 

 that has been done the dissector of the abdomen ceases work till 

 the body is re-turned, when he will re-examine the anatomy 

 of the inguinal region in association with the formation of hernia, 

 and afterwards proceed to the investigation of the abdominal 

 cavity and its contents. 



HERNIA. 



The anatomy of the abdominal wall, in the regions where 

 hernia most frequently occurs, is of such great importance to 

 the surgeon that special attention must be paid to it by the 

 dissector. 



