468 DIGESTIVE SYSTEM OF THE OX 



grooves for the S-shaped portion of the duodenum (Impressio duodenalis) may be found dorsal 

 and lateral to the portal fissure. (5) The fossa of the gall-bladder (Fossa vesica felleai) is distinct 

 when that organ is full. In the calf the omasal impression is small, and the abomasal one large in 

 correspondence with the relative sizes of these two sacs. 



The portal fissure is a well-defined rounded depression, situated dorsal to the 

 omasal impression. It contains, besides the vessels and duct, several large hepatic 

 "lymph glands. Dorsal and lateral to it a part of the pancreas is attached. 



The dorsal border is short and thick; it usually extends backward a short 

 distance beyond the upper part of the last rib. It presents the large, thick, quad- 

 rilateral caudate lobe, and a deep depression for the right kidney and adrenal. 



The ventral border is short and thin and has no interlobar incisures. 



The right (or lateral) border is marked by the umbilical fissure, in which the 

 ligamentum teres is attached in the young subject. 



The left border presents the oesophageal notch below its middle; the notch is 

 much shallower than in the horse. Above this it is practically median in position, 

 and lodges the posterior vena cava, which is partially embedded in the gland. Be- 

 low the notch the border extends an inch or two (ca. 2.5 to 5 cm.) to the left of the 

 median plane, opposite the ventral third of the sixth rib or intercostal space. 



The right lateral ligament attaches the dorsal border to the anterior part of 

 the sublumbar region. The ligament of the caudate lobe passes to the ventral 

 surface of the right kidney. There is no left lateral hgament. The falciform liga- 

 ment is generally present, but the ligamentum teres is usually found only in yoimg 

 subjects. The lesser omentum leaves the liver along a line extending from the 

 CBSophageal notch to the portal fissure. The only distinct lobes in the adult are 

 the caudate and papillary. The latter is best seen in the soft specimen; it is a 

 tongue-like mass which partly overlaps the portal vein and fissure.^ 



A gall-bladder (Vesica fellea) is present. This is a pear-shaped sac, four to 

 six inches (ca. 10 to 15 cm.) long, which lies partly in contact with the visceral 

 surface of the liver (to which it is attached), but largely against the abdominal wall 

 at the ventral part of the tenth or eleventh intercostal space. It may be regarded 

 as a diverticulum of the bile-duct, enlarged to form a reservoir for the bile. Its 

 neck is continued by the cystic duct (Ductus cysticus), which joins the hepatic 

 duct at an acute angle just outside of the portal fissure, to form with it the bile- 

 duct (Ductus choledochus) . The latter is short and enters the second bend of the 

 S-shaped curve of the duodenum, i. e., about two feet (ca. 60 cm.) from the pylorus. 

 The opening of the duct is at the end of a papilla or ridge-like fold. Several small 

 ducts (Ductus hepatocystici) open directly into the gall-bladder. 



The wall of the gall-bladder consists of serous, muscular, and mucous coats. The muscular 

 tissue consists of unstriped fibers which run in various directions; externally many are longitudinal, 

 while internally (and especially at the neck) they are chiefly circular. The mucous membrane is 

 covered by a cylindrical epithehum and contains numerous groups of branched tubular glands. 

 The cystic and bile ducts have a similar structure. 



In the new-born calf the Uver is relatively much larger than in the adult. The visceral 

 surface presents, below the portal fissure, a rounded eminence, which is caused by the pres- 

 ence in the underlying gland substance of a large venous sinus into which the umbilical and portal 

 veins empty. A large vessel, the ductus venosus, leads from this sinus directly to the posterior 

 vena cava. The umbihcal fissure is deep and partially divides the gland into two chief lobes. 



THE PANCREAS 



The pancreas of the ox is irregularly quadrilateral in form, and lies almost 

 entirely to the right of the median plane. Its weight is about the same as that of 

 the horse. Its dorsal surface is related to the liver, right kidney, crura of the 

 diaphragm, posterior vena cava, and coeliac and anterior mesenteric arteries; it is 



^ The hver of the ox might be regarded as consisting of dorsal, ventral, caudate, and papillary 

 lobes. Pathological adhesions of the ventral part of the hver to the diaphragm and reticulum 

 are often present in dissecting-room subjects. 



