DISSECTION OF THE NECK. 69 



this nerve curves round the sub-clavian artery, and 

 then continues forward into the neck as described. 

 After giving off other branches to the lungs, the 

 vagus descends along the oesophagus, and finally 

 divides into two branches, one of which passes to the 

 dorsal side of the oesophagus, and is there joined by a 

 similar branch from the right vague ; the other division 

 passes to the ventral side of the oesophagus, where it 

 joins the similar ventral branch of the right vagus. 

 The two new trunks thus formed can be traced to the 

 stomach ; each ends in a plexus of nerve-fibres, which 

 are distributed to the stomach and make connections 

 also with the solar plexus of the coeliac ganglia. 



18. The Thoracic Sympathetic Trunk. From the 

 inferior cervical ganglion two branches pass to the 

 large \st thoracic ganglion, one above and one 

 below the sub-clavian artery, forming a ring known as 

 the " anmilus of Vietissens." From this annulus one 

 or more small branches may be given off toward the 

 heart to join the cardiac plexus. 



The I St thoracic ganglion is very large, and besides 

 its connections with the inferior cervical gives off the 

 following branches : a. A large branch, the vertebral, 

 passing forward to join with the two lower cervical 

 spinal nerves, b. A branch to the ist thoracic spinal 

 nerve, c. A branch to the 2d thoracic spinal, d. A 

 branch to the 3d thoracic spinal, and sometimes, e, a 

 branch to the 4th thoracic spinal. 



From the ist thoracic ganglion the sympathetic 

 trunk continues backward along the spinal column, 

 and at intervals shows ganglionic swellings, usually one 

 for each rib after the 3d or 4th ; but this is sometimes 

 irregular. From each ganglion a branch passes to the 



