628 THE SYMPATHETIC KEEVES AND GAXGLIA. 



The great prevertebral plexuses comjirise three large aggrega- 

 tions of nerves, or nerves and ganglia sitnated in front of the spine, and 

 occupying respectively the thorax, the abdomen, and the pelvis. They 

 are single and median, and are named respectively the cardiac, the 

 solar, and the hypogastric plexus. These plexuses receive branches 

 from both the gangliated cords above noticed, and they constitute 

 centres from which the viscera are supplied with nerves. 



The cranial ganglia of the sympathetic are the ophthalmic, spheno- 

 palatine, submaxillary, and otic, which, being intimately united with 

 the fifth cranial nerve, have already been described along with that 

 nerve. They are also more or less directly connected with the upper 

 end of the sympathetic gangliated cords ; but it will be unnecessary to 

 give any special description of them in this place. 



THE CERVICAL PAUT OF THE GANGLIATED COED. 



In the neck, each gangliated cord is deeply placed behind the sheath 

 of the great cervical blood-vessels, and in contact with the muscles 

 which immediately cover the fore part of the vertebral column. It 

 comprises three ganglia, the first of which is placed near the base of 

 the skull, the second in the lower part of the neck, and the third 

 immediately above the head of the first rib. 



THE UPPER CEEVICAL GANGLION. 



This is the largest ganglion of the great sympathetic cord. It is 

 continued superiorly into an ascending branch, and tapers below into 

 the connecting cord, so as to present usually a fusiform shape ; but 

 there is considerable variety in this respect in different cases, the 

 ganglion being occasionally broader than usual, and sometimes con- 

 stricted at intervals. It has the reddish -grey colour characteristic of 

 the ganglia of the sympathetic system. It is placed on the larger 

 rectus muscle, opposite the second and third cervical vertebra, and 

 behind the internal carotid artery. 



Connection ivith spinal nerves. — At its outer side the superior cervical 

 ganglion is connected with the first four spinal nerves, by means of 

 slender cords, which have the structure pointed out in the general 

 description as being common to the series. 



The circumstance of this ganglion being connected with so many as four spinal 

 nerves, together with its occasionally constricted appearance, is favoui-able to 

 the view that it may be regai'ded as consisting of several ganglia which have 

 coalesced. 



Connection with cranial nerves. — Small twigs connect the ganglion or 

 its cranial cord with the second ganglion of the pneumo-gastric, and 

 with the ninth cranial nerve, near the base of the skull ; and another 

 branch, which is directed upwards from the ganglion, divides at the 

 base of the skull into two filaments, one of which ends in the second 

 (])etrosal) ganglion of the glosso-pharyngeal nerve ; while the other, 

 entering the jugular foramen, joins the ganglion of the root of the 

 pneumo-gastric. 



Besides the branches connecting it with cranial and spinal nerves, 

 the first cervical ganglion gives oflF also the ascending branch, the 

 upper cardiac nerve, pharyngeal nerves, and branches to blood-vessels. 



1. ASCENDDTG BRANCH AND CRANIAL PLEXUSES. — The ascending 



