THE SYMPATHETIC NERVES OF THE NECK 375 



vertebrae, is reddish gray in color, fusiform in shape, and lies 

 on the rectus anticus major behind the internal carotid vessels. 



Branches. An ascending branch runs alongside the internal 

 carotid artery, and in the canal separates into an outer division, 

 forming the carotid plexus, and an inner, forming the cavernous 

 plexus. 



The carotid plexus lies external to the artery. It sends one 

 or more filaments to the sixth nerve as it lies alongside the 

 artery, and some to the Gasserian ganglion; to the spheno- 

 palatine ganglion it sends the large deep petrosal nerve, which 

 joins the large superficial petrosal to form the Vidian; it also 

 sends the small deep petrosal, which communicates with 

 Jacobson's nerve by joining the tympanic plexus. 



The cavernous plexus, in the cavernous sinus, lies below and 

 internal to the internal carotid. It sends a branch to the 

 third nerve, one to the fourth, several to the ophthalmic divi- 

 sion of the fifth, the sympathetic root to the ophthalmic ganglion 

 and filaments to the pituitary body. 



Both these plexuses supply terminal filaments which form 

 plexuses on the ophthalmic and cerebral arteries and sub- 

 branches. 



A descending branch to the middle cervical ganglion. 



External branches to the first four spinal nerves, to the 

 ganglia of the vagus, the petrous ganglion of the glossopharyn- 

 geal, and to the hypoglossal. 



Three internal branches, viz., pharyngeal. laryngeal, and 

 the superior cardiac nerve. The pharyngeal runs to the pharynx 

 and unites with the branches of the ninth and tenth cranial, 

 forming the pharyngeal plexus. 



The laryngeal branch joins the superior and external laryn- 

 geal nerves. 



The superior cardiac nerve descends on the longus colli behind 

 the common carotid sheath, and crosses the inferior thyroid 

 artery and recurrent nerve. , It rises from the upper ganglion, 

 and receives filaments from a communicating branch between 

 it and the middle ganglion. On the right side it crosses the 

 subclavian, and runs along the innominate artery to join 

 the deep cardiac plexus behind the aorta. It receives many 

 branches from the vagus and sympathetic. The left descends 

 along the left carotid to enter the superficial cardiac plexus 

 in front of the aorta. 



