LAKGE INTESTINE. 1211 



1. Caecum. The caecum is a wide, short cul-de-sac, consisting of the portion of 

 the large bowel below the valvula coli. It. lies in the right iliac region, and from 

 its medial and posterior, part a worm-shaped outgrowth, the vermiform process, is 

 prolonged (Fig. 951). 



2. Colon Ascendens. The ascending colon ascends vertically in the right 

 lumbar region as far as the inferior surface of the liver: here the gut bends to 

 the left, forming the flexura coli dextra (O.T. hepatic flexure), and then passes trans- 

 versely across the abdomen, towards the spleen, as the transverse colon. 



3. Colon Transversum. The transverse colon, a loop of intestine which passes 

 across the abdominal cavity in an irregular looped manner. It ends at the 

 inferior extremity of the spleen. There it turns downward, forming the flexura 

 coli sinistra (O.T. splenic flexure), and passes into the descending colon. 



Haustra (Sacculations) 



Appendices epiploicae 



FIG. 950. LARGE INTESTINE. 



A piece of transverse colon from a child two years old. The three chief characteristics of the large intestine 

 sacculations, taenise, and appendices epiploicae are shown. 



4. Colon Descendens. The descending colon runs down on the left side, from 

 the splenic flexure to the rectum. 



It is usually divided into the following parts : 



(a) Descending colon, which extends down to the crest of the ilium. 



(&) The iliac colon extends from the crest of the ilium to the superior aperture 



of the pelvis, where it is succeeded by the pelvic colon. 

 (c) The pelvic colon is a large loop of intestine which is usually found in the 



pelvis. The iliac and pelvic portions of the colon taken together are 



sometimes described as the colon sigmoideum. 



5. Intestinum Rectum. The rectum, the terminal part of the large bowel, 

 succeeds the pelvic colon, and ends in the anal canal, which opens on the surface 

 at the anal orifice. 



In its course the large bowel is arranged in an arched manner around the 

 small intestine, which lies within the concavity of the curve (Fig. 912). 



In length, the great intestine is equal to about one-fifth of the whole intestinal 

 canal, and usually measures between 5 and 5| feet (180 to 195 cm.). Its breadth 

 is greatest at the caecum, and from this with the exception of a dilation at the 

 rectum it gradually decreases to the anus. At the csecum it measures, when 

 distended, about 3 inches (75 mm.) in diameter; beyond this it gradually 

 diminishes, and measures only 1 J inches (37 mm.) or less in the descending and 

 iliac divisions of the colon. 



The large intestine, with the exception of the rectum and vermiform process, 

 may be easily distinguished from the regularly cylindrical small intestine by (a) 

 the presence of three longitudinal bands the tsenise coli running along its surface 

 (Fig. 950); (V) by the fact that its walls are sacculated; and (c) by the presence 

 of numerous little peritoneal processes, known as appendices epiploicse, projecting 

 from its serous coat. In addition, the larger intestine is usually wider than the 

 small, but reliance cannot be placed on this character, for the jejunum is often 

 indeed, generally wider than the empty and contracted descending colon. 



Taenise Coli. In the large bowel, unlike the small, the longitudinal fibres of 

 the muscular coat do not form a complete layer, continuous all round the tube, 



