788 
ANATOMY AND PATHOLOGY 
Cervicothorocic Dorsal intercostal v., a,n L. azygos Parietal pleura Dorsal (posterior) 
ganglion Sympathetic trunk /// /(tiemiazygos)^ v / ^'^'J" intercostal a. 
Brachial 
plexus 
Cranial (sup ) 
vena cava 
Internal thoracic a.Sv^' 
Visceral pleura 
Recurrent laryngeal 7T 
Cardiac br of vagus n. Pericardiacophrenic a. 
Figure 24. — Left mediastinum illustrating the azygos venous system. 
mately one minute. Histamine phosphate yields 
results similar to betahistine hydrochloride, 
while nicotinic acid produces only slight in- 
creases in blood flow in the basilar artery (Fig- 
ure 33). 
ARTERIAL SUPPLY AND AUTONOMIC 
INNERVATION OF THE STOMACH OF 
SHEEP AND CALF 
The ruminant animal has three developmental 
dilatations of the lower esophagus, namely the 
reticulum, omasum and rumen, and they are 
collectively referred to as the forestomach. The 
true stomach, comparable to the stomach in 
man, is called the abomasum in ruminant mam- 
mals. Because of the increasing interest in the 
study of physiology of digestion and its rela- 
tion to the cardiovascular system, a study of 
the normal arterial supply to the ruminant 
stomach was undertaken.^^'^^ 
Based on a study of ten adult sheep, the 
arterial supply to the ovine stomach is derived 
from the celiac artery. Cranial mesenteric and 
celiac arteries originate by a common trunk 
from the abdominal aorta in most cases. The 
common hepatic artery (Figure 34), carrying 
with it a dense plexus of autonomic nerves, 
courses through the lesser omentum to a posi- 
tion near the porta hepatis where it splits into 
right and left hepatic, cystic, right gastric, and 
gastroduodenal arteries. The gastroduodenal ar- 
tery contributes blood supply to the descending 
duodenum and then courses to the greater cur- 
vature of the abomasum. The left gastric artery 
(Figure 35) and its large gastroepiploic branch 
are the major arteries supplying the abomasal 
fundus and body. The left gastric artery anas- 
