440 



DIGESTIVE SYSTEM OF THE HORSE 



The author recently-observed in a horse, which weighed about 1200 pounds f spleen ^^^'^^^^^^^^ 

 lOM pounds, and measured 26 inches in length and 11 inches m width at the base The ventra 

 end was situated opposite the lower part of the seventh intercostal space ^^^he new-born foal 

 the weight is about lOto 12ounces (ca. 300 gm.). There does not seem to ^^ any constant relation 

 to the body-weight. For example, the spleen of a colt of medium size about ten months old 



\, Intestinal 

 impression 



weighed three and a half pounds, while it" often weighs less than two Pou^s in hor"^ighi°g 

 1000 to 1200 pounds. The chief variation in outline consists of increase of width, especially ot the 

 dorsal part. 



It extends obliquely in a curved direction, corresponding to the left part of the 

 greater curvature of the stomach, from the left crus of the diaphragm to the ventral 



third of the tenth or eleventh nb. It 

 presents for description two surfaces, 

 two borders, and two extremities. 



The parietal or lateral surface (Fa- 

 des parietalis) is convex, and hes chiefly 

 against the diaphragm, but is in contact 

 with the upper parts of the last two ribs 

 and usually to a small extent with the 

 flank at the lumbo-costal angle. 



The visceral or medial surface (Fa- 

 des visceralis) is in general concave. It 

 is divided into two unequal parts 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 (Fades gastrica) is molded on the 

 greater curvature of the stomach; it 

 is about two inches (ca. 5 cm.) wide. 

 The area behind the ridge (Fades intes- 

 tinalis) is much more extensive; it is 

 related to the small colon, the left parts 

 of the great colon, the small intestine, 

 and the great omentum. It may be 

 marked by one or two fissures. 



The anterior border (Margo crani- 

 ahs) is concave and thin, being wedged 

 in between the diaphragm and the 

 greater curvature of the stomach. 



The posterior border (Margo cau- 

 dalis) is convex and thin. 



The dorsal extremity or base (Ex- 

 tremitas dorsalis) is beveled, and fits into 

 the interval between the left crus of 

 the diaphragm and sublumbar muscles 

 above, and the saccus cacus of the stomach and the left kidney below. When 

 hardened in situ, it shows an impression (Fades 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 caecus of the stomach and the left kidney opposite 

 to the last thoracic vertebra; the posterior basal angle usually lies against the 

 upper part of the left flank, just behind the last rib.^ 



The ventral extremity or apex (Extremitas ventralis) is small and varies in 

 position. It is commonly found opposite the tenth or eleventh rib, a handbreadth 

 or more above the costal arch, but may be further forward and higher. 



Fig. 376.- 



^'Is- 



-Spleen of Horse, Hardened in situ 

 CERAL Surface. 

 a, Dorsal extremity or base; b, c, anterior and poste- 

 rior basal angles; d, anterior border; e, cut edge of sus- 

 pensory ligament ; f, g, splenic artery and vein in hilus. 

 The area marked intestinal impression is related to the 

 first coil of the small colon. The area enclosed by the 

 suspensory ligament is non-peritoneal. 



1 It is uncommon to find the spleen extending more than two or three inches behind the last 

 rib; on the other hand, the posterior basal angle may lie just at the last rib. 



