SYSTEM OF THE HORSE 
440 
DIGESTIVE 
The author recently observed in a horse, which weighed about 1200 pounds, a spleen which weighed 
1014 pounds, and measured 26 inches in length and 11 inches in width at the base. The ventral 
end was situated opposite the lower part of the seventh intercostal space. In the new-born foal 
the weight is about 10to 12 ounces (ca. 300 gm.). There does not seem to be any constant relation 
to the body-weight. For example, the spleen of a colt of medium size about ten months old 
weighed three and a half pounds, while it often weighs less than two pounds in horses weighing 
1000 to 1200 pounds. The chief variation in outline consists of increase of width, especially of the 
dorsal part. 
Tt 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 rib. It 
presents for description two surfaces, 
two borders, and two extremities. 
The parietal or lateral surface (Fa- 
cies parietalis) is convex, and lies chiefly 
against the diaphragm, but is in contact 
with the dorsal 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- 
cies 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 (Facies gastrica) is molded on the 
ereater curvature of the stomach; it 
is about two inches (ca. 5 em.) wide. 
The area behind the ridge (Facies 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- 
alis) is concave and thin, being wedged 
in between the 
Fic. 376.—SpLeen or Horse, HARDENED in situ; Vis- 
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. 
above, and the saccus execus of the stomach and the left kidney below. 
diaphragm and_ the 
ereater 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 
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 cxecus of the stomach and the left kidney at the 
seventeenth 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. 
: 1 Tt 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. 
