BRANCHES OF THE ABDOMINAL AORTA 661 
branch (Ramus dorsalis) gives off a spinal branch (Ramus spinalis) which passes 
through the intervertebral foramen, gives twigs to the membranes of the spinal 
cord, perforates the dura, and reinforces the ventral spinal artery. A muscular 
branch passes to the muscles and skin of the back. The ventral branch (Ramus 
ventralis) is much the larger. It descends, at first almost in the middle of the 
intercostal space between the intercostal muscles, then gains the posterior border 
of the rib, and is subpleural. Each is accompanied by a vein and nerve, the artery 
being in the middle and the vein in front. At the ventral part of the space it unites 
with a ventral intercostal branch of the internal thoracic or the musculo-phrenic 
artery. It supplies the intercostal muscles, the ribs and the pleura, and gives off 
perforating branches which pass out to the serratus ventralis, the abdominal 
muscles, and the skin. 
3. The phrenic arteries (Aa. phrenic) are two or three small vessels which 
arise at the hiatus aorticus from the ventral aspect of the aorta, often by a common 
trunk. They supply the crura of the diaphragm. In some cases they arise in 
common with an intercostal artery. 
BRANCHES OF THE ABDOMINAL AORTA 
The collateral branches of the abdominal part of the aorta are distributed 
chiefly to the walls and contents of the abdominal cavity, but some branches are 
Posterior 
<yenda cava 
Fic. 573.—PLan or Brancues oF Catrac ARTERY OF HORSE. 
. 
1, Coeliac artery; 2, gastric artery; 3, hepatic artery; 4, splenic artery; 5, posterior gastric artery; 6, anterior 
gastric artery; 7, esophageal branch; 8, gastro-duodenal artery; 9, pancreatico-duodenal artery; 10, right gastro- 
epiploic artery; 11, pyloric artery; 12, left gastro-epiploic artery; /3, short gastric branches of splenic. 
supplied to the spinal cord and its membranes, and others extend into the pelvis 
and to the scrotum. The visceral branches are the cceliac, anterior mesenteric, 
