470 DIGESTIVE SYSTEM OF THE SHEEP 
The right or posterior part is wide and thin and is often divided into two branches. 
The duct leaves the posterior part of the ventro-lateral (or right) border and enters 
the duodenum about twelve inches (ca. 30 em.) further back than the bile-duct. 
THE SPLEEN 
The spleen has an elongated, elliptical outline, both extremities being thin, 
rounded, and similar in size. 
Its average weight is about two pounds (ca. 900 gm.), or about 6 per cent. of 
the body-weight. Its average length is about 20 inches (ca. 50 em.), its width 
about 6 inches (ca. 15 em.), and in the 
Dorsal extremity middle its thickness is about an inch (ca. 
2 to 3 cm.). 
The dorsal extremity lies under the 
dorsal ends of the last two ribs, and may 
extend back as far as the first lumbar 
transverse process. The ventral extrem- 
ity is usually opposite the eighth or ninth 
rib, about a handbreadth above its june- 
tion with the cartilage. The parietal sur- 
face is convex, and is related to the dia- 
phragm. The visceral surface is concave, 
and is related chiefly to the left face of the 
rumen, but also usually to a narrow ad- 
jacent area of the reticulum. The dorsal 
part is attached to the left crus of the dia- 
phragm and the left surface of the rumen 
by peritoneum and connective tissue; the 
ventral part is free. The hilus is situated 
on the dorsal third of the visceral surface, 
near the anterior border. 
Splenic vein 
Splenic artery 
Hilus 
About one-half of the visceral surface of the 
spleen is attached directly to the stomach and is 
therefore not covered by peritoneum; the line of re- 
flection of the :atter crosses the surface obliquely, 
from the upper part of the posterior border to ; 
the anterior border below its middle. Similarly U 
there is a narrow uncovered area on the upper 
Ventral extremity part of the parietal surface along the anterior | 
border. The hilus is not a groove, but a simple 
Fic. 403.—SpLeen or Ox; VISCERAL SURFACE. depression. When hardened in situ, the organ is 
1, Area of attachment to rumen (non-peritoneal); 2, seen to be somewhat twisted, so that the upper 
posterior border; 3, line of peritoneal reflection. part of the parietal surface faces dorsally and | 
forward, while below it is directed laterally. In 
some cases the spleen is considerably longer than 
is stated above. and may extend to the ventral end of the eighth rib. Not uncommonly there are 
pathological adhesions of the ventral part of the spleen to adjacent structures. 
DIGESTIVE SYSTEM OF THE SHEEP 
The lips are thin and mobile; the upper one is marked by a very distinet 
philtrum, and otherwise is not bare. 
The anterior part of the hard palate is prominent and smooth, forming the — | 
so-called dental pad or plate. On the posterior part of this area there are two 
f 
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