THE VASCULAR SYSTEM. 
133 
blood may not be forced back into the heart by the con- 
traction of the muscular coat of the arteries. 
The branches of the thoracic aorta are as follows: the 
right and left coronary, arising 
from the aorta immediately 
beyond its exit from the ventricle, are distributed to the 
walls of the heart. 
From the arch of the aorta arise 
two large branches; first, the innominate, giving origin to 
the right subclavian supplying 
right and left carotids supply- 
ing the head and neck; and 
second, the left subclavian, sup- 
plying the left arm, brain, and 
sternum (Fig. 72). Ten pairs 
of intercostal arteries supply 
the intercostal spaces, muscles, 
of the back, and the spinal cord. 
Two bronchial arteries go to 
the lung tissue. Two to four 
esophageal arteries are distrib- 
uted to the esophagus. Two 
or three pairs of lumbar ar- 
teries pierce the muscles of the 
back. 
Fic. 72. CuHrer ARTERIES OF THE 
TRUNK, VENTRAL ASPECT. 
ar, Arch of the aorta; bc, innomi- 
nate; ce, cceliac axis; cd, cau- 
dal; e, gastric; f, gastric; gr, 
gastric; gas, gastroduodenalis; lp, 
hepatic; ht, location of heart; ten, 
intercostals; ic, external iliac; it, 
internal iliac; #/, iliolumbar; im, 
inferior mesenteric; Js, left sub- 
clavian; /pl, left pulmonary; m, 
splenic; o, splenic; 7, right pul- 
monary; re, renal; sp, splenic 
trunk; sms, superior mesenteric; 
sm, spermatic or ovarian; s, ad- 
renolumbalis; 1, 2, 3, 4, 5, and 6, 
lumbar arteries. 
blood to the arm, and the 
