CERVICAL PART OF CORD. 361 



The great prevertebral plexuses comprise three large aggregations of nerves, 

 or nerves and ganglia, situated 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 the cerebro-spinal nerves, as well as from both the gangliated 

 cords above noticed, and they constitute centres from which the viscera are supplied 

 with nerves. 



CERVICAL PART OF THE GANGLIATED CORD. 



In the neck, the gangliated cord is deeply placed behind the great cervical blood- 

 vessels, being embedded in the fascia forming the back of the carotid sheath, and 

 resting on 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 close to the head of 

 the first rib. 



UPPER CERVICAL GANGLION. 



This is the largest ganglion of the great sympathetic cord, 20 mm. or more long 

 and 4 6 mm. wide. 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 diiferent cases, the ganglion being 

 occasionally shorter and broader than usual, and sometimes constricted at intervals. 

 Ib has the reddish-grey colour characteristic of the ganglia of the sympathetic 

 system. It is placed on the rectus anticus major muscle opposite the second and 

 third cervical vertebrae, lying behind the internal carotid artery, and to the inner 

 side of the vagus nerve. 



Connection with spinal nerves. At its outer side, the superior cervical 

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

 which belong to the group of grey rami communicantes. The branches to the 

 third and fourth nerves often pierce the rectus anticus major muscle ; and they may 

 be given off from the upper part of the cord, instead of directly from the ganglion. 



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

 together with its occasionally constricted appearance, is favourable to the view that it may be 

 regarded as consisting of several ganglia which have coalesced. 



The superior cervical ganglion is considered by Gaskell to be a distal or collateral ganglion 

 It receives its cerebro-spinal fibres, which constitute the cervical splanchnic* of Gaskell. from 

 the upper dorsal nerves, through the cervical part of the sympathetic cord. 



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

 cranial cord with the lower ganglion of the pneumo-gastric, and with the twelfth 

 cranial nerve, near the base of the skull ; and another branch (n. jugularis], which 

 is directed upwards from the ganglion, divides at the base of the skull into two 

 filaments, one of which ends in the petrosal ganglion of the glosso-pharyngeal 

 nerve ; while the other, entering the jugular foramen, joins the ganglion of the root 

 of the pneumo-gastric. 



From the lower part of the ganglion a filament sometimes runs forwards and downwards 

 to join the external laryngeal nerve. This branch is described as normal by many anatomists, 

 but according to Drobnik it is only exceptionally present. 



Besides the branches connecting it with cranial and spinal nerves, the first 

 cervical ganglion gives off also the ascending branch, pharyngeal branches, the upper 

 cardiac nerve, and branches to blood-vessels, as well as two or three filaments which 

 pierce the prevertebral muscles to supply the upper cervical vertebra? and their 

 ligaments. 



