192 



ANATOMY FOR NURSES 



[Chap. XI 



the union of the two vertebrals.^ These arteries are joined in such 

 a manner as to form a complete circle, and this arrangement 

 serves (1) to equalize the circulation of the blood in the brain, 



and (2) in case of destruction of one 

 of the arteries, it provides for the 

 blood reaching the brain through 

 other vessels. 



The subclavian arteries. — The 

 right subclavian arises at the divi- 

 sion of the innominate, and the left 

 subclavian from the arch of the 

 aorta. The subclavian arteries are 

 the first portions of a long trunk 

 which forms the main artery of the 

 upper limb, and which is artificially 

 divided for purposes of description 

 into three parts; viz.: (1) Subcla- 

 vian, (2) Axillary, and (3) Brachial. 



The subclavian artery passes a 

 short way up the thorax into the 

 neck, and then turns downward to 

 rest on the first rib. At the lower 

 border of the first rib it ceases to be 

 called subclavian, and is continued 

 as the axillary. It gives off large 

 branches to the brain, back, chest, 

 and neck. 



The axillary artery passes through 

 the axilla, lying to the inner side of 

 the shoulder joint and upper part of 

 the arm. It gives off branches to 

 chest, shoulder, and arm. 



The brachial artery (continuation 

 of the axillary) extends from the ax- 

 FiG. 122. — Deep Axterior iHarv space to just below the bend 



View of the Arteries of the ' ..... 



Arm. Forearm, and Hand. of the elbow, where it divides intO 



1 The vertebral arteries are branches given off from the subclavian. They as- 

 cend on either side of the vertebral column, pass through the foramen magnum, 

 and at the base of the brain unite to form the basilar artery. 



