378 



DIGESTIVE SYSTEM OF THE HORSE 



pounds in horses weighing 1000 to 1200 pounds. The chief variation in outline consists of increase 

 of width, especially of the dorsal part. 



It extends obliquely in a curved direction from the left crus of the diaphragm 

 and the saccus csecus of the stomach to the ventral third of the ninth or tenth rib. 

 It presents for description two surfaces, two borders, and two extremities. 



The parietal or external surface (Facies parietalis) is convex, and lies chiefly 

 against the diaphragm, l)ut is in direct contact with the upper parts of the last 

 two ribs and to a small extent with the flank at the lumbo-costal angle. 



The visceral or internal surface (Facies visceralis) is in general concave. It 

 is divided into two unequal portions by a longitudinal ridge; on this is a groove, 

 the hilus, in which the vessels and nerves are situated. The area in front of the 

 ridge (Facies gastrica) is moulded on the great curvature of the stomach; it is about 

 two inches (ca. 5 cm.) wide. The area behind the ridge (Facies intestinalis) is 



Base 



Posterior basal angle 



Attachment of suspensory \ 

 ligament J 



Anterior basal angle 

 Splenic artery 

 Splenic vein 



Anterior border 



Fic. 277 — Spleen of Horse, Hardexed in situ. Viscerai- Surface. 

 The area marked inte.stinal impression is related to the first coil of the small colon. 



much more extensive; it is related chiefly to the small colon, the small intestine, 

 and the great omentum. It may be marked ])y one or two fissures. 



The anterior border (Margo anterior) is concave and thin. 



The posterior border (Margo posterior) is convex and thin. 



Th(^ base or dorsal extremity is })eveled, and fits into the interval between 

 the left kidney and the left crus of the diaphragm and the psoas major. When 

 hardened in situ, it shows an impression (Facies renalis) where it lies against the 

 kidney. The left extremity of the pancreas touches it also. The anterior basal 

 angle fits in between the saccus caucus of the stomach and the left kidney; the 

 posterior basal angle usually lies against the flank just behind the last rib. 



The apex or ventral extremity is small ; it lies — when the stomach is not full — 

 between the left lobe of the liver and the left dorsal jwrtion of the colon; when 



