336 ABDOMEN 



of the upper branches of the right and left colic vessels and 

 their anastomoses with the middle colic vessels. 



Flexura Coli Sinistra (O.T. The Splenic Flexure of the 

 Colon). The left flexure of the colon is situated in the left 

 hypochondriac region in close relation with the lower end of 

 the spleen, the tail of the pancreas, and the lateral border 

 of the left kidney. It is closely attached (i) to the left ex- 

 tremity of the anterior border of the pancreas, by the left 

 portion of the transverse meso-colon ; (2) to the stomach, by 

 the upper end of the left border of the greater omentum ; (3) 

 and to the abdominal surface of the diaphragm, opposite the 

 eleventh rib in the mid-axillary line, by the phrenico-colic 

 ligament. It is a more fixed flexure, and it is also a more 

 acute flexure than the right flexure of the colon. 



Colon Descendens. The descending colon commences 

 at the left flexure of the colon, in the left hypochondriac 

 region, descends along the lower part of the lateral border 

 of the left kidney, turns slightly medially to the apex of 

 the lower pole of the kidney (Fig. 155), and then descends, 

 vertically, to the left iliac crest, where it becomes the iliac 

 colon. Its length varies from i o to 15 cm. (four to six inches). 

 Like the ascending colon it is covered in front and on each 

 side by peritoneum, and its posterior surface is in relation 

 with the extra-peritoneal fat which separates it from the fascia 

 in front of the quadratus lumborum and the medial part of 

 the aponeurosis of origin of the transversus abdominis. Its 

 posterior and anterior relations are similar to those of the 

 ascending colon (see p. 333). 



Colon Iliacum. The iliac portion of the colon commences 

 at the termination of the descending colon, at the level of the 

 upper and posterior part of the left iliac crest. It passes down- 

 wards and forwards to the region of the anterior superior iliac 

 spine, and then turns medially, along the line of the inguinal 

 ligament, to the brim of the pelvis minor, where it becomes the 

 pelvic colon. Its length varies from 12.5 to 15 cm. (five to six 

 inches). It does not possess a mesentery, but is covered with 

 peritoneum anteriorly and along its sides. Posteriorly, it is 

 separated by the extra-peritoneal fat from the iliacus, the 

 psoas major, the femoral nerve (O.T. anterior crural), which 

 lies in the groove between the two muscles, and its termina- 

 tion is in front of the left external iliac artery. 



Before removing the ascending colon and the transverse 



