488 DIGESTIVE SYSTEM OF THE PIG 
obliquely and projects considerably into the latter. A fold of mucous membrane 
(Frenulum ilei) passes from each side of the ileo-czecal opening. The colon has at 
first about the same caliber as the execum, but becomes gradually smaller. It lies 
chiefly to the left of the median plane, behind the stomach. Most of it is arranged 
in three close, double spiral coils in the mesentery, in relation with the floor of the 
abdomen ventrally, the stomach and liver in front, the caecum and small intestine 
behind, and the small intestine on the right. On emerging from this spiral laby- 
rinth it passes at first forward in the sublumbar region to the right of the median 
plane, and, on reaching the stomach and right end of the pancreas, turns to the left. 
It then passes backward, on the ventral surface of the pancreas, and in relation to 
the medial part of the left kidney, inclines medially, and is continued at the pelvie 
inlet by the rectum. This terminal part is closely attached by a short mesentery to 
the sublumbar region. The rectum is usually surrounded by a quantity of fat. 
The cecum has three longitudinal muscular bands and three rows of sacculations, 
which are continued a short distance on the colon. The spiral colon has two bands 
and two series of sacculations, which, however, gradually disappear in the centrif- 
ugal part. The solitary nodules are numerous, and appear as round prominences, 
2-3 mm. in diameter, often with a crater-like depression. The last Peyer’s patch 
of the small intestine is continued a variable distance in the caecum, and there are 
often patches in the first part of the colon. 
THE LIVER 
The liver is relatively large, its average weight in the adult being about four 
pounds (ca. 1.5-2 kg.). It is thick centrally, but the circumference is thin. It is 
divided by three deep interlobar incisures into four principal lobes—right lateral, 
right central, left central, left lateral; the last of these is usually considerably the 
largest. On the upper part of the right lateral lobe, is the caudate lobe, which is 
clearly marked off by a fissure and is often partially subdivided by a secondary 
fissure. That part of the right central lobe which lies below the portal fissure and | 
to the left of the gall-bladder and cystic duct is homologous with the quadrate lobe | 
of man. Much the greater part is to the right of the median plane. The parietal | 
surface is extremely convex in conformity with the curvature of the diaphragm, to | 
which it is chiefly related! A small part of the surface is in contact with the | 
abdominal floor in the xiphoid region and ventral to the right costal arch. Its 
most anterior part reaches to a transverse plane through the ventral part of the | 
sixth rib or intercostal space. The visceral surface is deeply concave; most of it | 
is related to the stomach, for which there is a correspondingly large and deep gastrie 
impression. There may be a duodenal impression on the upper part of the right | 
lateral lobe, but no renal impression exists, as the right kidney does not touch the 
liver. The fossa for the gall-bladder (Fossa vesice fellexe) is mainly on the right | 
central lobe, but also in part on the adjacent surface of the left centrallobe. The pos- 
terior vena cava enters the dorsal border of the caudate lobe and soon becomes entirely — 
embedded in the gland substance, emerging only at its passage through the dia- 
phragm. The esophageal notch is large and is occupied mainly by the large right 
crus of the diaphragm. The right lateral border extends backward to the upper 
part of the last intercostal space. The left lateral border is opposite the ninth 
intercostal space and eighth rib. The ventral border les on the abdominal floor 
a short distance (ca. 8-5 em.) behind the xiphoid cartilage. 
The coronary ligament resembles that of the horse. The faleiform ligament is 
very short or absent in the adult, and is attached to the diaphragm just below the 
1The description here given is based on the appearance of the organ as hardened in situ, 
which differs radically from that of the soft organ. It also differs much in shape in young and 
adult subjects. 
