THE NECK, ANTERIOR. 109 



seventh cervical vertebra, sympathetic cord, cardiac nerves, 

 recurrent laryngeal, lung, and pleura. 



Below : Lung and pleura, loop of recurrent laryngeal, 

 and sympathetic nerves. 



The Second Portion of Right and Left Subclavian Arteries. 



This lies behind the scalenus anticus muscle. 



In addition to the fasciae, skin, and muscles above given 

 as being in front of the first portion of the right artery, 

 there are the scalenus anticus muscle and the phrenic nerve 

 (separated from the artery by the scalenus muscle). 



Behind : Apex of the lung and pleura. Scalenus 

 medius. 



Below : Pleura and lung. 



Above : The brachial plexus. 



Third Portion of the Subclavian Artery, Right and Left. 



This extends from the outer border of the scalenus anti- 

 cus to the lower border of the first rib. 



In front : The skin, layers of fascia, platysma, clavicular 

 nerves, the suprascapular artery (if the arm be elevated) ; 

 the external jugular and subclavian veins ; the supra- 

 scapular and transverse cervical form a plexus in front of the 

 artery before they empty into the external jugular vein. 



The nerve to the subclavius muscle. 



Behind : Scalenus medius, the lower or third trunk of 

 the brachial plexus. 



Below : The posterior of the two grooves upon the 

 upper surface of the first rib. 



Above : The cords and the first trunk (see page 312) 

 of the brachial plexus. The posterior belly of the omo- 

 hyoid muscle. 



Branches of the Subclavian Artery. 



From the First Portion. Vertebral, thyroid axis, internal 

 mammary. 



