THE GREAT SYMPATHETIC NERVOUS SYSTEM. 887 



fibres of Remak, which they contain in large quantity. With these nucleated 

 fibres are associated fine double-contoured fibres — myelin fibres — which proceed 

 from the communicating rami, or afferent filaments supplied by the spinal nerves ; 

 these fibres often leave the ganglia to pass directly to organs. 



In describing the sympathetic chain, it is divided into five sections : a cranial^ 

 cervical, dorsal, lumbar, and sacral. 



1. Cranial Portion of the Sympathetic. 



This is composed of the spheno-palatine, ophthalmic, and otic ganglia, all of 

 which communicate with the superior cervical ganglion. Their description has 

 been given with that of the fifth cranial pair of nerves. 



2. Cervical Portion of the Sympathetic. 



The cervical section of the ganglionic chain is formed by two large ganglia 

 placed one at the top, the other at the bottom, of the neck, and united to each 

 there by an intermediate cord. 



A. Superior Cervical or Guttural Ganglion (Fig. 480, 1). — This 

 ganglion is a very elongated fusiform body, lying beside the internal carotid 

 artery, comprised with it in a particular fold of the membrane forming the 

 guttural pouch, and therefore situated in front of the transverse process of 

 the atlas, in proximity to the glosso-pharyngeal, pneumogastric, spinal, and 

 hypoglossal nerves, as well as the inferior branch of the first cervical pair. All 

 these nerves communicate with the ganglion by slender filaments, and in this 

 way form around it a veritable plexus, which has been designated the guttural 

 plexus by Veterinary Anatomists. 



Afferent Branches. — These are communicating filaments belonging to the 

 nerves already enumerated. They do not possess sufficient importance to merit 

 particular mention. We may notice the existence of the filaments supplied by 

 the inferior branches of the first four cervical nerves. 



Efferent Branches. — These are : 1. Branches accompanying the internal 

 carotid arteiy into the cranium. 2. A thick fasciculus which reaches the origin 

 of the three terminal divisions of the common carotid. 3. Small filaments to 

 the membrane of the guttural pouch and the wall of the pharynx. 



The following are the principal anatomical characters of these three orders 

 of branches : — 



a. The satellite branches of the internal carotid artery arise at the superior 

 extremity of the ganglion. They may vary in number. Two are generally 

 found, of unequal volume — a posterior, and an anterior, which is the smallest. 

 They interlace around the internal carotid in anastomosing with each other, and 

 with that vessel enter the cavernous sinus, where they form, by their divisions, 

 a little plexiform apparatus named the cavernous plexus, the various branches of 

 which connect it with several of the cranial nerves. Among these branches are 

 remarked : 1. Some filaments joined to analogous filaments from the opposite 

 side, on the transverse anastomosis which unites the two internal carotids in the 

 cavernous sinus. 2. A branch lying beside the great petrosal nerve, and 

 concuiTing in the formation of the Vidian nerve, which enters the spheno-palatine 

 ganglion. 3. A ramuscule going to the ophthalmic ganglion, in company with 

 fibres from the ophthalmic branch of the fifth pair. 4. Several filaments passing 

 to the Gasserian ganglion. 5. Branches which mix with the fibres of the three 

 motor nerves of the eye. 



