416 



DIGESTIVE SYSTEM OF THE HORSE 



tine, and the greater omentum. The borders between these surfaces are 

 termed the curvatures. The lesser curvature (Curvatura ventricuU mmor) 

 is very short, extending from the termination of the oesophagus to the junc- 

 tion with the small intestine. When the stomach is in situ, its walls are here in 

 contact, and the cardia and pylorus close together. "■ The greater curvature (Cur- 

 vatura ventriculi major) is very extensive. From the cardia it is first directed 

 dorsally and curves over the left extremity; it then descends, passes to the right, 

 crosses the median plane, and curves upward to end at the pylorus. Its left part 

 is related to the spleen, while its ventral portion rests on the left parts 

 of the great colon. The left extremity (Extremitas sinistra) has the form of a 

 rounded cul-de-sac termed the saccus csecus ; it lies ventral to the left crus of the 

 diaphrag-m, and so beneath the dorsal part of the sixteenth and seventeenth ribs. 

 It is related to the pancreas and the termination of the great colon behind and the 

 base of the spleen laterally. The right or pyloric extremity (Extremitas dextra) 



is much smaller and is continuous with 

 the duodenum, the junction being in- 

 dicated by a marked constriction. It 

 lies just to the right of the median 

 plane, and about two inches (ca. 5 cm.) 

 lower than the cardia; it is in contact 

 with the visceral surface of the liver. 

 About two or three inches (ca. 5 to 8 

 cm.) from the pylorus there is a con- 

 striction which marks off the antrum 

 pyloricum from the rest of the right 

 sac. The oesophageal orifice is termed 

 the cardia; it is situated at the left 

 end of the lesser curvature, but about 

 eight to ten inches (ca. 20 to 25 cm.) 

 from the left extremity.^ The oesopha- 

 gus joins the stomach very obliquely. 

 The opening is closed by the sphincter 

 cardiae and numerous folds of mucous 

 membrane. The pylorus is the open- 

 ing into the intestine. Its position is 

 indicated externally by a distinct con- 

 striction. Internally it presents a cir- 

 cular ridge caused by a ring of mus- 

 cular tissue — the sphincter pylori. 



The stomach is held in position 

 mainly by the pressure of the sur- 

 The following peritoneal folds connect 



Fig. 3"»6. — E\ertep Stomach of Horse from which 



THE MUCOLTS IVIeMBRAXB HAS BEEN REMOVED. 



O, CEsophagus; D, duodenum; b, circukir layer; 

 c' , intc-rnal oblique fibers; c" , loop around cardia; c'", 

 transition of internal to external oblique fibers; d, fibers 

 connecting the two branches of the cardiac loop; p, 

 antral sphincter; p' , pyloric sphincter. (EUenberger- 

 Baum, Anat. d. Haustiere.) 



rounding viscera and by the oesophagus, 

 it with the adjacent parts: 



1. The gastro-phrenic ligament (Lig. gastrophrenicum) connects the greater 

 curvature, from the cardia to the left extremity, with the crura of the diaphragm. 

 This lea^-es a narrow area uncovered with peritoneum, and here the stomach is 

 attached to the diaphragm by areolar tissue. 



tion. 



' The more expressive term "inrisura angularis" haS' been suggested and is worthy of adop- 



' The position of the cardia varies of course with the excursion of the diaphragm. It is 

 usually an inch or more (ca. 3 cm.) to the left of the median plane and \'entral to the vertebral end 

 of the fourteenth rib. When the diaphragm is contracted the cardia may be six inches (ca. 15 cm.) 

 below the level of thespine; when the diaphragm isrelaxed, the interval may be reduced to about 

 two inches (ca. .5 cm.). 



