THE ABDOMINAL CAVITY 285 



angles to the line of mesenteric attachment, i.e. upwards and to 

 the right or downwards and to the left. Owing to the " lie " of 

 the mesentery ; endeavours to draw the gut downwards and to the 

 right or upwards and to the left cannot meet with much success. 



The right infra- colic compartment, bounded above by the 

 root of the transverse meso-colon, to the right by the ascending 

 colon, and to the left by the root of the mesentery, is roughly 

 triangular in shape (Fig. 88). It can be exposed by drawing 

 the greater omentum upwards and displacing the coils of small 

 intestine downwards and to the left. The peritoneum on its 

 posterior wall covers the lower pole of the right kidney, the 

 second and third parts of the duodenum, a small part of the 

 head and neck of the pancreas, and the right ureter and psoas 

 major muscle (Fig. 88). 



Owing to the protection which it receives from the greater 

 omentum, this compartment is rarely infected by a downward 

 spread, and as its lower extremity is closed (Fig. 88), it is not com- 

 monly infected by an upward spread from the pelvis. Primary 

 infection is rare ; it is usually due to the vermiform process 

 (P- 33 1 )- Drainage may be obtained through the appendicular 

 wound by means of a tube passed upwards and to the left, 

 medial to the ascending colon and behind the greater omentum. 



The left infra-colic compartment is bounded to the right by 

 the root of the mesentery and to the left by the descending and 

 iliac cola ; below, it is bounded on the left side by the ascending 

 part of the pelvic meso-colon, but on the right side it opens 

 freely into the pelvis (Fig. 88). It can be exposed by drawing 

 the greater omentum upwards and displacing the small intestine 

 upwards and to the right. The peritoneum on its posterior wall 

 covers the lower pole of the left kidney, the inferior surface of 

 the body of the pancreas, and the duodeno-jejunal flexure 

 above ; the left ureter, the inferior mesenteric and superior 

 hsemorrhoidal vessels, and the left psoas major below. 



Either infra-colic compartment may be the site of a 

 tuberculous abscess, following the breaking down of caseous 

 mesenteric lymph glands. 



The right para-colic gutter lies along the lateral side of 

 the ascending colon, and its floor is formed by the peritoneal 

 reflection from the gut to the lateral wall of the abdomen. Above, 

 it opens into the hepato -renal recess of Morison ; below, it 

 passes round or behind the caecum and communicates with the 

 pelvis over the medial border of the psoas major. Infection of 



