378 DISEASES OF THE G ASTRO-INTESTINAL TRACT. 



THE INTESTINES. 

 Congenital Deformities and Displacements. 



Absence of the whole, or large parts, of the intestinal tract 

 is sometimes met with in monstrosities. Lesser developmental 

 defects are not uncommon. The anus may be wanting 

 imperforate anus and likewise the rectum and lower part of 

 the colon. MeckeVs diverticulum (Fig. 170) is a remnant of 



FIG. 170. 



Meckel's diverticulum (Dennis). 



the omphalo-mesenteric duct of foetal life. It is a cylindrical 

 appendage, of the same structure as the small intestine, and 

 arises from the latter, opposite the mesenteric attachment, 

 about a meter above the ileo-csecal valve. Such diverticula 

 are sometimes the cause of intestinal obstruction (Fig. 171). 

 The caecum and ascending colon are sometimes situated on 



