Clinical Anatomy of the European Hamster 
over the left kidney to the spleen, forming the ven- 
tral layer of the lienorenal ligament {lig. lienore- 
nale), from which it reflects to the dorsal surface of 
the stomach to form the dorsal layer of the greater 
omentum. Passing over the dorsal stomach, past the 
pylorus to the cranial surface of the proximal duo- 
denum, it winds around the hepatic artery, portal 
vein and common bile duct to reach the ventral sur- 
face of the stomach. This reflection forms the ven- 
tral layer of the greater omentum. The sheath then 
winds around both the costal and renal surface of 
the spleen before passing to the left kidney to form 
the dorsal layer of the lienorenal ligament. Moving 
dorsally to cover the lateral surface of the left kid- 
ney, it then reflects back on the abdominal wall, 
which it follows uninterruptedly on the left side 
back to the ventral midline. 
5.5.2 Craniomesocolic Viscera and 
Relations 
5.5.2.1 Esophagus 
The abdominal portion of the esophagus, about 
25 mm long, begins in the muscular part of the dia- 
phragm at the level of the eighth or ninth thoracic 
vertebra, 6 mm ventral to the aortic hiatus, and just 
dorsal to the central tendon of the bifurcation into 
lateral leaflets (Fig. 4-11). From the esophageal 
foramen, the esophagus runs between the visceral 
surface of the left lateral lobe of the liver and the 
cranial margin of the forestomach, crossing the 
pylorus and the first duodenal flexure cranially. It 
enters the forestomach at the margo plicatus, the 
border between the glandular and forestomachs 
(Figs. 5-10, 5-11), slightly to the left of the midline. 
As in the thoracic region, the abdominal esophagus is lined with 
keratinized stratified squamous epithelium surrounded by striated 
musculature (Fig. 4-23). The matte white mucosa is thrown into small 
longitudinal folds in its empty and contracted state (Fig. 4-22). 
The gastrophrenic ligament {lig. gastrophreni- 
cum), which becomes the point of origin for the 
greater omentum, extends dorsally from the lesser 
curvature of the forestomach to the diaphragm and 
there envelops the abdominal portion of the esoph- 
agus lying cranial to the liver. 
5.5.2.2 Stomach 
The European hamster receives its nourishment 
124 
mainly from plants and utilizes a forestomach for 
predigestion. The compound stomach is thus di- 
vided by a distinct constriction into a larger blind 
forestomach (proven triculus) and a smaller true or 
glandular stomach (ventnculus glandularis) (Fig. 
5-10). The European hamster differs from the rat 
(Wells, 1968) and the mouse (Theiler, 1972) in 
which no such constrictions are found. The com- 
pound stomach lies in the cranial abdominal region 
(regio abdommis cranialis) and completely occu- 
pies the left hypochondrium [regio hypochondriaca 
sinistra) (Figs. 5-8, 5-9). Depending upon the 
distention of the stomach, it protrudes to a greater 
or lesser extent into the corresponding right side of 
the abdominal cavity, where it presses against the 
lateral abdominal wall. In general, one-fourth of 
the glandular stomach lies to the right, and three- 
fourths to the left of the median sagittal plane of 
the body, the glandular stomach lying to the right 
of the forestomach (Figs. 5-8, 5-9). The most 
cranial part of the forestomach lies at the level of 
the 12th thoracic vertebra, while the greater curva- 
ture of the glandular stomach extends caudally to 
the level of the second or third lumbar vertebra. 
The weight of the fully distended stomach (fore- 
stomach and glandular stomach) is about 1 1 g and 
10 g for male and female hamsters, respectively, 
while the empty stomach weighs approximately 3 g 
for both sexes (Tables 3, 6). 
When markedly distended, the forestomach 
ranges from 45 to 50 mm long and from 15 to 
25 mm wide (Figs. 5-1 1 , 5-12). The grayish-white 
forestomach lies in the cranial portion of the peri- 
toneal cavity near the left abdominal wall and ex- 
tends obliquely in a caudoventral direction towards 
the umbilical region (Fig. 5-13). Its cranial surface 
usually impinges upon the left lateral lobe of the 
liver and, in formalin-fixed animals, leaves an im- 
pression of this lobe. From dorsal to ventral, the 
caudal surface is related to the spleen, the left part 
of the pancreas and the head of the caecum, respec- 
tively (Fig. 5-9). When very distended, the con- 
tents of the forestomach can be seen through the 
serous surface. 
The epithehal lining of the forestomach is pale, almost white in 
color, and is thrown into delicate transverse and slightly curled folds 
(Fig. 5-14). At the blind end of the forestomach, these folds become 
distinctly more elevated, sometimes attaining a height of up to 7 mm 
(Fig. 5-14). Under magnification these folds easily can be misinter- 
preted as papillomas. The forestomach is lined with simple keratinized 
