

THE SUBCLAVIAN ARTERY 



583 



Peculiarities. The ascending branch of the transverse cervical frequently arises directly 

 from the thyrocervical trunk; and the descending branch from the third, more rarely from the 

 second, part of the subclavian. . 



Thyrocervical artery 



Scalenus anterior 



Musculophrenic artery~( JJJMT^- 



Common carotid artery 

 Innominate artery 

 Internal mammary artery 



Perforating branches 



Superior epigastric artery 



Inferior epigastric artery 



External iliac artery 



FIG. 522. The internal mammary artery and its branches. 



3. The internal mammary artery (a. mammaria interna) (Fig. 522) arises from 

 the under surface of the first portion of the subclavian, opposite the thyro- 

 ^rvical trunk. It descends behind the cartilages of the upper six ribs at a distance 



