452 HEALTH AND DISEASE 



of branches, some of which are distributed to the walls of the chest and 

 abdomen, while others go to the various organs they contain. The former 

 set include: (l) 13 posterior intercostal vessels, which run downward 

 between the ribs and give off branches upward to the muscles of the back 

 and to the spinal cord. The first intercostal artery is derived from the 

 superior cervical artery; the second, third, and fourth from the subcostal 

 branch of the dorsal. (2) The phrenic, a branch going to the diaphragm 

 or midriff. (3) Branches to the muscles of the loins. 



The second group comprise: (l) The bronchial arteries to the air-tubes 

 and oesophagus or gullet. (2) The cseliac axis, a short thick vessel, which, 

 after leaving the under surface of the aorta, divides into three unequal 

 branches ^ The Splenic ^ The Gastric ^ The Hepatic 



The first goes to the spleen, the second to the stomach, and the third to 

 the liver. A little farther back it gives off (3) the great mesenteric artery, 

 a short vessel of considerable size, whose branches are distributed to the 

 large and small intestines. The next to appear are (4) the renal arteries, 

 two short thick vessels, which spring from the sides of the aorta and enter 

 the substance of the kidney. Still farther back come (5) the spermatic 

 vessels. These arteries, two in number, are of considerable length, and 

 take a peculiar winding course downward to reach the testicles. In the 

 female the uterine and ovarian arteries spring from this point, and, as 

 their names imply, supply the uterus and the ovaries. Then comes the 

 small mesenteric, whose branches are distributed to the posterior part of 

 the large bowel, which is not supplied by the large mesenteric. Finally, 

 the posterior aorta divides into two pairs of vessels, one pair going to the 

 right and the other to the left. These are distinguished as 



1. The Internal Iliac Arteries. 2. The External Iliac Arteries. 



The Internal Iliac Artery breaks up into several divisions, which 

 convey blood to the organs within the pelvis the bladder, rectum, prostate 

 gland, as well as parts of the uterus and vagina in the female and the 

 penis in the male. They are: (l) the two last lumbar arteries; (2) the 

 internal pudic artery; (3) the lateral sacral artery; (4) the ilio-lumbar 

 artery; (5) the gluteal artery; (6) the ilio - femoral artery; (7) the 

 obturator artery. 



The External Iliac Artery, on leaving the aorta, runs down the 

 inner side of the pelvis in an oblique direction backwards and outwards. 

 On reaching the anterior border of the pubis it enters the thigh and takes 

 the name of the femoral artery. In its course it gives off the circumflex 

 iliac artery, which is distributed to the flank and to the thigh. A small 



