THE ABDOMEN 721 



Superior. — The posterior part of the inferior surface of the 

 diaphragm. Inferior. — ^The bend of the gastro-colic omentum, 

 where the two anterior or descending layers are folded backwards 

 to become the two posterior or ascending layers. Left. — The 

 spleen ; the gastro-splenic omentum ; the lieno-renal ligament ; and 

 the left border of the gastro-colic omentum. 



In a great many cases that part of the small sac which is con- 

 tained within the gastro-colic omentum is very limited in its down- 

 ward extent, on accoxmt of adhesions having formed between the 

 layers of the great omentum. 



Foramen of Winslow. — ^This is the opening by which the great 

 and small sacs of the peritoneum communicate with each other. 

 It is situated behind the right or free border of the gastro-hepatic 

 omentum, on a level with the body of the 12th thoracic vertebra. 

 Its direction is fonvards and to the right, and it admits of the 

 passage of one finger, and in some cases of two fingers. It is, 

 however, often blocked by inflammatory products. 



Boundaries — Anterior. — ^The right or free border of the gastro- 

 hepatic omentum, containing bet^veen its two layers (i) the common 

 bile-duct, to the right side ; (2) the hepatic artery, invested by the 

 hepatic plexus of sympathetic nerves, to the left side ; (3) the vena 

 |x>rtae, which lies between these two, on a plane posterior to 

 both ; and (4) lymphatic vessels. Posterior. — ^The inferior vena 

 cava covered by peritoneum. Superior. — ^The caudate lobe of the 

 liver. Inferior. — ^The first part of the duodenum, and the hepatic 

 artery in the first part of its course, as it curves forwards and up- 

 wards from the coeliac axis. Wlien the foramen is blocked by 

 inflammatory products, if fluid should be effused into the small 

 sac the condition known as hydrops saccatus would result. It is 

 possible for a loop of bowel to pass through the foramen, thus 

 forming one variety of internal hernia. 



Peritoneal Fosss or Pouches. — The peritoneum presents in certain situa- 

 tions small pockets, which are known as peritoneal fossae or pouches. 

 Their importance consists in the fact that a small portion of intestine may 

 enter one or other of them and become strangulated, thus constituting an 

 internal hernia, which, except in the cases of the inguinal pouches, is called 

 a retro-peritoneal hernia. The fossae, according to their situation, are called 

 duodenal, duodeno-jejunal, peri-caecal, and intersigmoid. 



Duodenal Fossae. — Four varieties of duodenal fossae are met with in con- 

 nection with the terminal part of the duodenum, namely, inferior duodenal, 

 superior duodenal, para-duodenal, and retro-duodenal (Jonnesco). 



The inferior duodenal fossa is the most common and largest. It is situated 

 on the left side of the terminal part of the duodenum -^nd opens upwards. 

 It is bounded in front by a thin triangular portion of ; ..itoneum, called the 

 inferior duodenal fold, which presents a free cresceudc border or base 

 superiorly. The fossa may admit the thumb, and may be nearly an inch 

 deep. It is said to be present in 75 per cent, of cases (Jonnesco). 



The superior duodenal fossa is less constant, and of smaller size, than the 

 inferior, and lies about an inch above it. It opens downwards, and its orifice 

 faces that of the inferior duodenal fossa. It may admit the tip of a finger. 

 It is bounded in front by a thin triangular portion of peritoneum, called the 

 superior duodenal fold, which presents a free crescentic border or base in- 

 feriorly. The fossa is said to be present in 50 per cent, of cases (Jonnesco). 



40 



