330 ABDOMEN 



large intestine have already been noted (p. 274); the positions 

 and relations of the individual parts must now be studied 

 more completely. 



Intestinum Crassum. The total length of the large 

 intestine varies from 134 to 167 cm. (4^ to 5^ feet). 

 The caecum, which is the shortest segment, is 64 mm. 

 (2f inches) long, and as broad, or broader, than it is 

 long. The ascending colon is from 12.5 cm. to 20 cm. 

 long (5 to 8 inches). The transverse colon, which is the 

 longest segment, is from 47.5 to 50 cm. in length (19 

 to 20 inches). The descending colon is somewhat shorter 

 than the ascending colon, varying from 10 to 15 cm. 

 (4 to 6 inches) in length. The iliac colon varies from 

 12.5 to 15 cm. (5 to 6 inches) in length; it is, therefore, 

 slightly longer than the descending colon. The length of 

 the pelvic colon varies very considerably, but averages from 

 40 to 42.5 cm. (16 to 17 inches). The rectum is the same 

 length as the iliac colon, 12.5 to 15 cm. (5 to 6 inches). 

 The pars analis recti, or anal canal, which forms the terminal 

 segment of the large intestine, is from 25 mm. to 37.5 mm. 

 (i to ij inches) long. The measurements given are those 

 which have been estimated on formol-hardened bodies, in 

 which the walls of the intestines are more or less contracted ; 

 they are, therefore, minimal measurements, and the lengths 

 of the various segments will be found to be greater in un- 

 hardened bodies, such as those met with in the post-mortem 

 room. 



The walls of all parts of the large intestine, except the 

 anal canal, are sacculated, but the sacculations vary in size 

 and number in the different segments, being largest and 

 least numerous in the rectum. During life, and after death, 

 the descending colon, the iliac colon, and the anal canal are 

 usually empty and their walls are contracted ; but the walls 

 of the other portions of the large gut are usually flaccid, 

 even when they are not distended. 



Intestinum Caecum. The caecum is the first section of the 

 large gut. It has the appearance of a sacculated pouch, 65 to 

 70 mm. (2 or 3 inches) long. Its width varies, but is rarely less 

 than its length, and it may be a little greater. It is continuous, 

 above, with the ascending colon, and on the left, with the 

 ileum, and with the vermiform process, which, in the adult, 

 is a diverticulum from the caecum. It is completely clothed 



