WESLEY D, ANDERSON 
775 
from the vagus, passes around the arch and 
ascends on the medial surface of the brachio- 
cephalic trunk beneath the subclavian artery to 
enter the carotid sheath in the caudal cervical 
region. In man, however, both recurrent laryn- 
geal nerves lie outside of the carotid sheath 
and generally ascend in the neck in the trache- 
sophageal groove. In the ruminant the vagus, 
after giving off the recurrent laryngeal nerve, 
continues along the ventrolateral surface of 
the descending thoracic aorta and at the hilus 
of the lung gives off small branches to the pul- 
monary, aortic, esophageal and cardiac plex- 
uses, and some fibers directly to the heart. Near 
the hilus of the lung each vagus bifurcates into 
a ventral and dorsal trunk. 
Sympathetic Nerves 
The thoracolumbar division of the autonomic 
nervous system is represented in the thorax by 
a chain of sympathetic ganglia embedded in 
endothoracic fascia and located lateral to the 
vertebral bodies and ventral to the angle of the 
ribs (Figures 12 and 13). In sheep, as in man, 
the first thoracic sympathetic ganglion and cau- 
dal cervical sympathetic ganglion are commonly 
fused into a large ganglion called cervicotho- 
racic, or because of its star-shape, the stellate 
