ABDOMINAL CAVITY 495 



dices epiploicce. The external longitudinal muscular fibres have 

 also been observed to be disposed in three flat bands. These 

 begin on the caecum at the base of the vermiform process. 

 From this they diverge, so as to take up positions on different 

 aspects of the gut. They are placed as follows: (i) One 

 in relation to the attached surface (taenia mesocolica) ; (2) 

 the second upon the anterior aspect (taenia libera) ; (3) and 

 the third along the medial aspect of the gut (tsenia omen- 

 talis), but, in the case of the transverse colon, the latter band 

 is in relation to the inferior aspect of the tube. The internal 

 circular muscular fibres are most distinct in the constrictions 

 between the sacculi, but constitute a thin uniform layer over 

 the entire extent of the gut. The submucous coat is in no 

 respect different from the corresponding coat in the small 

 intestine. 



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

 Colon). The splenic flexure is situated in the left hypo- 

 chondriac 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 to the left extremity 

 of the anterior border of the pancreas by the left portion 

 of the transverse meso-colon, to the stomach by the upper 

 end of the left border of the greater omentum, and to 

 the abdominal surface of the diaphragm, opposite the eleventh 

 rib in the mid-axillary line, by the phrenico-colic ligament. 

 It is, therefore, a more fixed, and it is also a more acute, 

 flexure than the hepatic flexure. 



Colon Descendens (The Descending Colon). The descend- 

 ing colon commences at the splenic flexure in the left hypo- 

 chondriac 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, and then descends, vertically, 

 to the left iliac crest, where it becomes the iliac colon. Its 

 length varies from 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 transversalis abdominis. Its posterior and anterior 

 relations are similar to those of the ascending colon (see 

 p. 491). 



The Iliac Colon. This portion of the colon commences 



