39 6 APPLIED ANATOMY. 



ilio-inguinal nerves near the crest. They should if possible be pulled aside, but if 

 cut are to be stitched together again. This gives only sufficient room to bring 

 a normal -sized kidney out of the wound; if the kidney is enlarged, Edebohls recom- 

 mends prolonging the incision along the crest of the ilium. This longitudinal 

 incision lies just back of the external oblique, traverses in its upper part the latissi- 

 mus dorsi (the fibres of which may be parted by blunt dissection) then the lumbar 

 fascia or anterior edge of the quadratus lumborum muscle, and lastly the transversa- 

 lis fascia behind the peritoneum (Fig. 411). 



Oblique Incision. When an incision for enlarged kidneys, tumors, or abscesses 

 is desired, it can be made obliquely downward and forward from the twelfth rib 

 anterior to its middle toward the anterior portion of the crest of the ilium. This 

 parts the fibres of the external oblique and divides the fibres of the transversalis 

 muscle obliquely, and those of the internal oblique almost transversely, but the 

 nerves (twelfth thoracic and iliohypogastric) are more readily drawn aside than if the 

 longitudinal incision is used. Care is to be taken not to go farther back than the 



Twelfth rib 



Latissimus dorsi 



Lumbar fascia 



Quadratus lumborum 



Erector spina; 



Vertebral aponeurosis ,,-i> 



Transversalis 



Internal oblique 

 External oblique 



FIG. 411. Lumbar incisions for operations on the kidney, showing the direction of the muscular fibres. 



middle of the twelfth rib, because the pleura usually crosses at that point to reach 

 the lower edge of the rib, or even a little below it at its posterior extremity. As 

 it is sometimes difficult to identify the twelfth rib, because it may be so short as to 

 be hidden beneath the muscles, the most certain way is to count downward from 

 the angle of the sternum opposite the second costal cartilage. There may be some 

 bleeding at the lower portion of the wound from the ascending branch of the deep 

 circumflex iliac artery near the anterior portion of the crest of the ilium. 



THE INTERIOR OF THE ABDOMEN. 



The abdominal cavity extends only to the brim of the pelvis; the pelvic cavity 

 is separate. The peritoneal cavity is not synonymous with the abdominal cavity: 

 some of the abdominal organs project comparatively little forward into it and, as 

 in the case of the kidneys, may be only partly covered with the peritoneum. The 

 peritoneal cavity includes the pelvis, so that an infection of the pelvic peritoneum 

 of necessity involves a part of the general peritoneal cavity. 



The peritoneum is a closed sac lining the abdomen and pelvis into which the 



