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 Ijy 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. phrenicEe) 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 



Fig. 57.3. — Plan of Branches of Cceliac Akteby of Horse. 

 1 Cceliac artery ; 2, gastric artery; S, hepatic artery; .}, splenic artery; ,5, posterior gastric artery; 6 anterior 

 gastric artery; 7, cesophageal branch; 8, gastro-duodenal artery; 9, pancreatico-duodenal artery;^ 10. nght gastro- 

 epiploic artery; 11, pyloric artery; /-', left gastro-epiploic artery; 13, 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. 



