340 A MANUAL OF ANA TOMY. 



behind, trachea, right lung, and pleura ; at the right, 

 right innominate vein, right pneumogastric nerve, right 

 lung and pleura; at the left, left common carotid artery : 

 at the ending of the artery, the trachea. 



Thoracic portions of the left common carotid and sub- 

 clavian arteries : 



The Left Common Carotid. Fig. 7 1 . Diag. 20. 



Arises from the middle of the upper surface of the 

 transverse aorta, passes upward and outward into the neck. 

 For rest of course see page 101. 



Relations (within thorax). In front, manubrium, origins 

 of the left sternohyoid and sternothyroid muscles, remains 

 of thymus gland, left innominate vein ; behind (and from 

 below upward), trachea, oesophagus, thoracic duct, recur- 

 rent laryngeal nerve ; at the right, innominate artery, 

 trachea, inferior thyroid veins ; at the left, left subclavian 

 artery (behind), left pneumogastric nerve, left lung and 

 pleura. 



The Left Subclavian Artery. Figs. 70, 71. Diag. 20. 



Is given off the transverse aorta at its terminus, extends 

 almost vertically upward into the neck, passing behind the 

 left sternoclavicular articulation. 



Relations (within the thorax). In front : First left costal 

 cartilage and adjacent portions of manubrium, left sterno- 

 clavicular joint, origins of the left sternohyoid and sterno- 

 thyroid muscles, left lung and pleura, left innominate vein, 

 left pneumogastric and cardiac nerves. Behind : Thoracic 

 duct, longus colli muscle, vertebrae. At the right : Left 

 common carotid (in front), trachea, left recurrent laryngeal 

 nerve, oesophagus (behind). 



For the continuation of the artery see page 1 08. 



