156 STUDIES IN ADVANCED PHYSIOLOGY. 



as the right common carotid. Further to the left on the 

 arch of the aorta the left subclavian artery arises, going to 

 the arm. From it, too, arises a left intra- vertebral artery 

 taking a similar course on the left side as the corresponding 

 one on the right.. The subclavian arteries are in each arm 

 continued as the brachial arteries, and at the elbow divide 

 into two arteries called the radial and the ulnar arteries. It 

 is the right radial artery at the wrist on which the nature of 

 the pulse is usually determined by the physician. These two 

 arteries then divide and in the hand form the anastomosing 

 branches which finally lead into the ultimate capillaries. 



Just below the arch of the aorta, but still in the chest, 

 numerous small arteries take their origin, which supply the 

 intercostal muscles. These are called the intercostal arter- 

 ies. Lying a little anterior to these in each case are small 

 arteries going to the lungs, called the bronchial arteries. 

 These must not be confounded with the pulmonary arteries 

 which carry the blood to the lungs. The bronchial arteries 

 carry arterial blood, intended for the nourishment of the 

 lung, and not sent to that place to be purified. 



At the point where the aorta pierces the diaphragm it 

 gives off the artery for that organ called the phrenic artery. 

 Immediately below the diaphragm a number of important 

 arteries leave the aorta frequently so close together as to 

 take a common origin. This common origin or common 

 trunk is, when present, called the cceliac axis. Frequently, 

 however, these arteries arise, although close together, still 

 separately. These arteries are the hepatic artery, going to 

 the liver, the splenic artery to the spleen, the gastric artery 

 to the stomach, and the pancreatic artery to the pancreas. 

 A little further down on the aorta the superior mesentery 

 artery carries arterial blood to the small intestines. Then 

 follow the two large renal arteries, then the spermatic arter- 

 ies going to organs in the pelvis, then the somewhat larger 

 inferior mesenteric artery supplying the large intestine, and 

 finally a few lumbar arteries supplying the body wall. At 

 this point the abdominal aorta divides into a right and left 



