DISSECTION OF THE NECK. 69 
this nerve curves round the sub-clavian artery, and 
then continues forward into the neck as described. 
miter Siving 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 ‘annulus of Veeussens.” From this annulus one 
or more small branches may be given off toward the 
heart to join the cardiac plexus, 
The 1st 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. 6. A branch tothe 1st thoracic spinal 
nerve,, 6, 2% branch to the 2d thoracic: spinal. a. A 
branch to the 3d thoracic spinal, and sometimes, ge, a 
branch to the ath thoracic spinal. 
From the 1st 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 
