THE SUBCLA VIAN ARTERY 



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The internal mammary artery (a. mammaria internet) (Fig. 459) arises from 

 the under surface of the first portion of the subclavian artery, opposite the thyroid 



Scalenus 

 anticits. 



Anterior intercosta 

 branches. 



Musculo- 

 phrenic. 





Thyroid axis. 



Common carotid. 

 Innominate. 



Internal mam- 

 mary. 



^Perforating 

 branches. 



Superior epi- 

 gastric. 



Deep epi- 

 gastric. 



\ External 

 iliac. 



FIG. 459. The internal mammary artery and its branches. 



axis. It descends behind the cartilages of the upper six ribs at a distance of 

 about half an inch from the margin of the sternum; and at the level of the sixth 

 intercostal space divides into the musculo phrenic and superior epigastric arteries. 



