Chap. xvn.] ABDOMINAL VISCERA. 325 



the serous membrane that encloses the descending 

 colon, that forms the sigmoid mesentery, and that 

 descends over the lumbo-sacral eminence into the 

 pelvis. The parietal attachment of the mesentery 

 measures, as a rule, about sij in.cjj.es. From its oblique 

 attachment it follows that, when haemorrhage takes 

 place in the abdomen on the right side of the 

 mesentery, the blood first is conducted into the right 

 iliac fossa, when on the left side, into the pelvis. 

 This may explain the circumstance that collections of 

 blood are more common in the right than in the left 

 iliac fossa. 



The length of the mesentery from the spine to the 

 bowel varies in different parts of the canal ; its 

 average length is eight inches. The longest part is 

 that which goes to "the coils of intestine that lie 

 between a point six feet from the duodenum, and a 

 point eleven feet from the same part of the gut 

 (Author).* Such coils will, therefore, include five feet 

 of the intestine, and the mesentery here may reach 

 the length of ten inches. These coils are apt to hang 

 in the pelvis, and may be easily herniated. The 

 length of the mesentery plays an important part 

 in hernia. If the fresh body of an adult be opened, 

 and the condition of the viscera and peritoneum be 

 normal, it will be fcmnd that it is impossible to drag 

 a loop of small intestine through the femoral canal 

 (artificially enlarged) on to the thigh, or down the 

 inguinal canal into the scrotum. In fact, no coil can, 

 in any part, be drawn out of the abdomen below a 

 horizontal line on a level with the spine of the pubes. 

 It is evident, therefore, that in femoral or scrotal 

 hernia the mesentery must be elongated or its attach- 

 ments lowered. 



The mesentery is relatively longest in infancy and 



* See " The Anatomy of the Intestinal Canal and Peritoneum 

 In Man," by the Author. London, 1885. 



