380 



DIGESTIVE SYSTEM OF THE HORSE 



extremity, where it is about an inch (ca. 2.5 to 3 cm.) wide.^ If the finger is passed 

 into the foramen from right to left, it enters the cavity of the lesser sac. If now 

 an opening is made in the great omentum and the other hand introduced through 

 it, the fingers of the two hands touch each other over the lesser curvature of the 

 stomach. The formation and boundaries of the lesser sac should now be examined 

 by spreading out the great omentum. It will ])e found that the latter now incloses 

 a considerable cavity behind the stomach; this is termed the omental cavity 

 (Bursa omentalis). Passing forward over the lesser curvature of the stomach, 

 we enter another space, the vestibule of the omental cavity (Vestibulum bursas 

 omentalis). This space is closed on the left by the gastro-phrenic ligament, below 

 and on the right by the lesser omentum, and dorsally by the gastro-pancreatic 

 fold, which is attached to the dorsal border of the liver and to the posterior vena 

 cava. Above the oesophageal notch the fingers can be passed around the border 

 of the liver and the vena cava till the coronary ligament is encountered. Thus 

 the vestibule is closed except (1) on the right, where it communicates with the cavity 



Fig. 278. — Diagram of General Arrangement of Peritoneum (of Mare) in Sagittal Tracing. 

 a, Pouch between rectum and roof of pelvis, continuous with 6, recto-genital pouch; c, vesico-genital pouch; 

 d, pouch below bladder and its lateral ligaments; /, lesser omentum; Int., small intestine. The arrow points 

 to the epiploic foramen (of Winslow). 



of the greater sac by the epiploic foramen; and (2) l^ehind, where it communicates 

 with the cavity of the omentum. 



The general arrangement of the great omentum has already lieen indicated. 

 We may now trace its line of attachment, which would correspond to the mouth of 

 the sac. Beginning at the ventral part of the great curvature of the stomach, the 

 line passes to the ventral face of the pylorus, then crosses obliquely the first part of 

 the duodenum to the point where the pancreas is adherent to it. Here it passes 

 to the anterior face of the terminal transverse part of the great colon, runs along 

 this transversely (from right to left), and continues for some ten or twelve inches 

 (ca. 25 to 30 cm.) on the small colon. It then forms an acute angle, passes inward 

 and forward along the small colon to the dorsal part of the hilus of the spleen, 

 where it blends with the suspensory ligament of the latter, and forms a recess 

 (Recessus lienalis) behind the saccus csecus of the stomach. It now passes along 

 the hilus of the spleen, and is continued to the great curvature of the stomach by the 

 gastro-splenic omentum. It is convenient to regard the spleen as being intercal- 



' The passage is sul)joct to a good deal of variation in caliber and is sometimes completely 

 occluded. 



