Clinical Anatomy of the European Hamster 
the lumbar vertebrae, all of the intra-abdominal 
organs are ventral to it. The craniomesocolic part 
of the abdominal aorta relates to the left lateral 
lobe of the liver, the glandular stomach, the duode- 
num, the transverse colon and assorted small in- 
testinal loops. At the level of the tenth thoracic ver- 
tebra, the aorta gives rise to the coeliac trunk {a. 
coeliaca); this, in turn, divides into the left gastric 
artery (a. gastnca sinistra), which runs to the car- 
dia of the glandular stomach; the splenic artery 
(<2. lienalis), which passes behind the stomach to 
the spleen; and the hepatic artery (a. hepatica). 
The latter gives off a gastroduodenal (a. gastro- 
duodenalis) and a right gastric {a. gastnca dextra) 
branch to the greater and lesser curvatures of the 
compound stomach, respectively (Fig. 5-34). Some- 
what distal to the coeliac trunk is the cranial mesen- 
teric artery (a. mesentenca cranialis), which crosses 
the caudal vena cava {v. cava caudalis) ventrally 
before giving rise to the caudal pancreatoduodenal 
artery {a. pancreatoduodenalis caudalis), to the 
pancreas and proximal duodenal loop. It runs on 
the cranial root of the mesentery ventral to the 
stomach before turning caudally between the 
jejunal-ileal loops. More caudal branches join with 
the caudal mesenteric artery {a. mesentenca cauda- 
lis) to supply the caudomesocolic region. 
Shortly after its point of origin, craniodorsal to 
the aortic bifurcation in the umbilical region {regie 
umbilicalis), the caudal vena cava runs cranially to 
the right of the aorta. At the level of the tenth and 
eleventh thoracic vertebrae, the vena cava turns 
dextroventrally and extends along the liver where 
it lies in close relation to the caudate lobe (Fig. 5- 
35). The caudal vena cava is subsequently invested 
completely by the right hepatic lobe before entering 
the thoracic cavity via the foramen venae cavae to 
the right of the falciform ligament. Shortly before 
the caudal vena cava passes through the diaphragm 
it receives the cranial phrenic veins (uv. phrenicae 
craniales). 
5.5.4 Greater Nerves of the Abdominal 
Cavity 
The vagus nerves enter the abdominal cavity on 
either side of the esophagus. The right vagus di- 
vides into two branches, of which the gastric branch 
{ramus gastncus uisceralis) extends to the caudal 
margin of the stomach, while the coeliac branch 
{ramus coeliacus) innervates the liver, spleen, 
pancreas and kidneys. The left vagus nerve gives 
off branches to the ventral surfaces of the stomach 
and liver. From the lumbar plexus {plexus lumba- 
lis), the iliohypogastric nerve {n. ilio hypo gastncus) 
can be followed between the kidney and the dorsal 
abdominal wall, where it enters m. quadratus 
lumborum. An additional branch of the lumbar 
plexus is the genitofemoral nerve {n. genitofemo- 
ralis), which passes obliquely over the psoas major; 
it crosses dorsal to the point of origin of the com- 
mon iliac vein {v. iliaca communis) (Kittel, 1953) 
to enter the pelvic cavity. The sympathetic trunk 
{truncus sympathicus) runs along the vertebral 
column medial to the origin of the psoas major. 
The splanchnic nerves {nn. splanchnici), which 
arise from sympathetic ganglia {ganglia trunci 
sympathici) within the thoracic cavity, accompany 
the aorta as it enters the abdominal cavity. The 
splanchnic nerves {nn. splanchnici major et minor) 
run beside the abdominal aorta and ventral to the 
adrenal glands to the coeliac ganglia {ganglia coeli- 
aca), which lie cranial to the origin of the cranial 
mesenteric artery. 
5.6 CAUDOMESOCOLIC REGION 
5.6.1 Caudomesocolic Peritoneum 
After forming the ventral layer of the greater 
omentum and passing dorsal to the transverse colon 
and on to the vertebral column at the caudal limit of 
the pancreas, the peritoneum runs caudally to 
cover the distal duodenum and forms the ventral 
layer of the mesentery. It covers the small intestine, 
then moves dorsally back to the vertebral column to 
form the dorsal mesenteric layer. Passing caudally 
along the dorsal wall, it invests the cranial and ven- 
tral margins of the rectum, from which it is re- 
flected ventrally onto the vagina and uterus, after 
covering the open interval between the rectum and 
female reproductive organs. This interval, the rec- 
togenital pouch {excavatw rectogenitalis), is en- 
tirely patent. After reflecting over the uterine fun- 
dus and body, the peritoneum dips again cau- 
dally to cover the bladder at the level of the cervix, 
where it forms the vesicogenital pouch {excauatio 
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