THE VISCERA. 213 



Structure. The mucous membrane presents : 1. Pocket-like recesses which 

 correspond to the elevations, and transverse folds corresponding to the inden- 

 tations on the outer surface of the intestine. 



2. Valvula Bauhini s. iko-c<Rcalis (see small intestine). The fold which 

 passes from the Caecum, has entirely the characters of its mucous membrane. 

 [Depressions, or alveoli, are seen on the surface of the m. membrane of 

 Caecum.] 



3. The opening of the vermiform process. 



4. The muscular coat consists of longitudinal fibres, which are bound up 

 hi three flat stripes (tcenia) as broad as a finger, and with transverse circular 

 fibres, by which the vesicular and cellular elevations (cellula. loculamentd) are 

 formed. 



5 Serous coat (perttonaum) is wanting on (upper part) the posterior surface 

 of the intestine. 



Vessels: branches of Art. and Ven. iko-colica (appendicularis, #0.), from me- 

 senter. superior. 



Nerves : come from plexus mesenteric. sup. 



443. b. The Colon, 



encircles the mesenteric intestine in the shape of a horse-shoe, 

 commencing without any distinct boundary line in the reg. iliaca 

 dextra, making a first curvature in the reg. hypochondriaca dex- 

 tra, a second in the reg. hypochond. sinistra, and a third in the 

 r. iliaca sinistra, in which it terminates with a sigmoid flexure. 

 Hence four portions arise. 



1 . Colon ascendens s. dextrum bounded below by the Csecum, 

 terminates as high as the gall bladder ; is covered before by the 

 peritonaeum and the abdominal walls (from which it is sometimes 

 separated by the small intestine), behind by M. quadrat, lumb. 

 and the right kidney (without peritonaeum and only fixed to the 

 uniting tissue). On the inner side lie small intestines (as on the 

 external), m. psoas and p. transv. duodeni. 



2. Colon transversum passes off at a right angle from the last, 

 below the stomach to a point under the spleen, is convex before, 

 concave behind, and very moveable (is often found in herniae). It 

 corresponds above with the liver and gall bladder, the stomach 

 and the inferior extremity of the spleen ; below, with the small 

 intestines ; before, with the abdominal walls (separated from it by 

 the two anterior layers of the great omentum) ; behind, with the 

 mesocolon transv. (mesentery, by which it is separated from 

 Doudenum and Pancreas). 



3. Colon descendens s. sinistrum passes first backwards, then 

 forwards, on the posterior abdominal wall, before m. quadrat, 

 lumbor. and left kidney; commences rather deeper than 1., and 

 terminates in the 



4. Sigmoid flexure, s.flexura iliaca, which lies in the fossa 

 iliaca sinistra, before, covered by the abdominal walls (in a state 



