370 CLINICAL APPLIED ANATOMY. 



the mesenteric glands. The parts of the small intestine most 

 likely to become entangled are those which lie in relation with 

 these structures. 



A Meckel's diverticulum sometimes acts as a band, producing 

 obstruction. The diverticulum, which is the remains of the 

 vitelline duct, usually arises from the small intestine within three 

 feet of the ileo-csecal valve. It may retain its connection with 

 the umbilicus, or its extremity may be free or acquire adhesions 

 to other structures. 



Strangulation in a peritoneal slit is sometimes observed. 

 The aperture is usually in the lower part of the mesentery of 

 the ileum, and is surrounded by an arterial arch formed by 

 the ileo-colic branch of the superior mesenteric artery and the 

 lowest of the vasa intestini tenuis. Slits may also occur in other 

 broad peritoneal folds, such as the great omentum, the broad 

 ligaments, the falciform ligament, the phrenico-colic ligament, or 

 even the mesentery of the appendix. 



Diaphragmatic hernia may be congenital, or acquired. 

 The congenital variety is due to persistence of the original 

 communication between the pleural and peritoneal cavities. 

 The opening is in the dorso-lateral region of the diaphragm, 

 and usuallv occurs on the left side, since the presence of 

 the liver on the right side aids the closure of the right 

 communication. The serous membranes of the two cavities 

 being continuous, the extruded viscera lie free in the 

 pleural cavity. The stomach usually passes into the cavity, 

 dragging in the colon and spleen by virtue of their omental 

 connections. The liver and pancreas sometimes enter as well. 

 The displacement of the stomach may lead to acute torsion of 

 the small omentum and partial strangulation. 



The acquired forms may be traumatic or spontaneous. 

 Traumatic hernia is due to wounds or ruptures of the diaphragm. 

 Spontaneous diaphragmatic hernias have definite sacs. They may 

 pass through the oesophageal opening or between the sternal and 

 costal portions of the diaphragm, never, it is said, through the open- 

 ings for the aorta or vena cava. In enteroptosis, the oesophageal 



