108 A MANUAL OF ANATOMY. 



The artery terminates on both sides of the body at the 

 lower border of the first rib, where the name for the arterial 

 trunk becomes the axillary. 



The artery is divided into three portions by the scalenus 

 anticus muscle. The first portion, internal to the muscle ; 

 the second, behind, and the third portion external to the 

 muscle. 



The right artery is three inches, the left about four inches 

 in length. 



Relations. 



First Portion of the Left Subclavian Artery. (Inserted 

 here to complete the description of the artery.) 



In front : Sternohyoid, sternothyroid, and sternomastoid 

 muscles. The left pleura and lung. The left innomi- 

 nate vein. (In the neck), internal jugular, vertebral, and sub- 

 clavian veins. Phrenic nerve (in the neck), cardiac nerves 

 (from sympathetic). Thoracic duct (root of neck). 



Behind (and internal) : CEsophagus, thoracic duct, sym- 

 pathetic and inferior ganglion, longus colli muscle, and spinal 

 column. Behind (and externally) : The lung and pleura. 



At the right : Trachea, recurrent laryngeal nerve, 

 cesophagus, and thoracic duct. 



At the left : Left lung and pleura. 



Right Subclavian Artery, First Portion. 



In front : Skin, superficial fascia, platysma, deep fascia 

 (two layers), the clavicular origins of the sternomastoid, 

 sternothyroid, and sternohyoid muscles. The subclavian 

 vein, the beginning of the innominate, end of the internal 

 jugular and vertebral veins. Pneumogastric and phrenic 

 nerves, the sympathetic cardiac branches. The artery is 

 surrounded by a loop of the sympathetic, called the ring 

 of Vieussens (annulus Vieussens). 



Behind : Longus colli muscle, transverse process of the 



