578 



THE ARTERIES. 



Inner side. 



Trachea. 

 (Esophagus. 

 Thoracic duct. 



Outer side. 

 Pleura. 



Behind. 



(Esophagus and thoracic duct. 

 Inferior cervical ganglion of sympathetic. 

 Longus colli and vertebral column. 



SECOND AND THIRD PARTS OF THE SUBCLAVIAN ARTERY (Fig. 347). 



The Second Portion of the Subclavian Artery lies behind the Scalenus anticus 

 muscle ; it is very short, and forms the highest part of the arch described by that 

 vessel. 



Kelatious. It is covered, in front, by the skin, superficial fascia, Platysma, 

 deep cervical fascia, Sterno-mastoid, and by the phrenic nerve, which is separated 

 from the artery by the ScaTenus anticus muscle. BeJtind, it is in relation with 

 the pleura and the middle Scalenus ; above, with the brachial plexus of nerves ; 

 below, with the pleura. The subclavian vein lies below and in front of the artery, 

 separated from it by the Scalenus anticus. 



PLAN or RELATIONS OF SECOND PORTION OF SUBCLAVIAN ARTERY. 



In front. 



Skin and superficial fascia. 

 Platysma and deep cervical fascia. 

 Sterno-mastoid. 

 Phrenic nerve. 

 Scalenus anticus. 

 Subclavian vein. 



Above. 

 Brachial plexus. 



Below. 

 Pleura. 



Behind. 



Pleura and Middle Scalenus. 



The Third Portion of the Subclavian Artery passes downward and outward 

 from the outer margin of the Scalenus anticus to the lower border of the first rib, 

 where it becomes the axillary artery. This portion of the vessel is the most 

 superficial, and is contained in a triangular space, the base of which is formed in 

 front by the Sterno-mastoid, and the two sides by the Omo-hyoid above and the 

 clavicle below. 



PLAN OF RELATIONS OF THIRD PORTION OF SUBCLAVIAN ARTERY. 



In front. 



Skin and superficial fascia. 

 Platysma and deep cervical fascia. 



Descending branches of cervical plexus. Nerve to Subclavius muscle. 

 Subclavius muscle, suprascapular artery, and vein. 

 The external jugular and transverse cervical veins. 

 The clavicle. 



Above. 



Brachial plexus. 

 Omo-hyoid. 



Below. 

 First rib. 



Behind. 

 Scalenus medius. 



