NERVES. 



(Esophageal Plexus. This surrounds the oesophagus, in the 

 posterior mediastinum, and is formed by both vagi, with 

 branches of the great splanchnic nerve and ganglion. It sup- 

 plies the oesophagus and pericardium. In the superior medi- 

 astinum the oesophagus gets branches from the right vagus 

 and left recurrent laryngeal. [695] 



Supra-clavicular Nerves. These descending branches of the 

 cervical plexus are cutaneous and pierce the deep fascia above 

 the clavicle. The sternal cross the inner end of the clavicle 

 and descend to the lower end of the manubrium. The clavic- 

 ular cross the middle third of the clavicle and descend to the 

 nipple. The acromial cross the outer third of the clavicle and 

 go to the shoulder. [624] 



Phrenic. From the neck, both nerves enter the thorax be- 

 tween the subclavian vessels, after crossing the first (left side) 

 or second (right side) part of the subclavian artery. Each 

 descends, in front of the root of the lung and between the 

 pericardium and pleura, to the diaphragm and divides into 

 branches supplying it, most of them after piercing it. The 

 left nerve, the longer, runs between the subclavian and carotid 

 arteries and crosses the vagus and aortic arch. The right nerve 

 accompanies the innominate vein and superior vena cava, but 

 is separate from the vagus. The branches are muscular, to the 

 diaphragm; pleura! and pericardiac (arising in the mediasti- 

 num); inferior vena caval; capsular, to the suprarenal; and 

 hepatic; (the latter three arise after the communication with 

 the diaphragmatic plexus). The phrenic communicates with 

 the solar plexus through the diaphragmatic plexus on the in- 

 ferior phrenic artery. [621] 



Brachial Plexus. This will be fully described with the 

 upper extremity. The branches to the thorax are as follows: 

 The nerve to the Subclavius crosses the subclavian artery to 

 reach its muscle. A communicating branch joins the phrenic. 

 The posterior scapular descends along the vertebral border of 

 the scapula, under cover of and supplying the Levator anguli 



[121] 



