DISSECTION OF THE HEAD AND NECK. 199 



artery, and under the occipital ; and above the first part of the trachea 

 its meets the cervical cord of the sympathetic, the two nerves then 

 uniting to form a common cord, which applies itself to the upper side 

 of the common carotid artery, and descends with it in the neck. 

 Between the foramen lacerum and the point where the nerve joins 

 the sympathetic it detaches the following branches : — 



1. Branches of Communication with the superior cervical ganglion. 



2. A Pharyngeal Branch is detached near the point where the vagus 

 passes under the occipital artery. It passes to the inner side of the 

 external carotid artery, and reaches the pharynx. There it unites 

 with the sympathetic and the pharyngeal branch of the 9th, forming 

 a plexus from which branches pass to the constrictors and mucous 

 membrane of the pharynx, and to the first part of the oesophagus. 



3. The Superior Laryngeal Nerve is given off near the termination 

 of the common carotid artery ; and, crossing beneath the external 

 carotid or the termination of the common carotid, it passes over the 

 pharynx to penetrate the thyroid cartilage at the anterior edge of 

 the thyro-pharyngeus muscle. Within the larynx, as will afterwards 

 be learned, it is distributed to the mucous membrane ; and also gives 

 branches to the pharynx, oesophagus, and root of the tongue. Near 

 its origin it detaches an external laryngeal branch, which passes to 

 the crico- thyroid and crico-pharyngeus muscles. 



The trunk of the vagus is sometimes distinctly gangliform at the 

 point of detachment of its superior laryngeal branch. This is the 

 ganglion of the trunk of human anatomy. 



The 11th Cranial Nerve, also called the Spinal Accessory Nerve 

 (Plate 32), issues from the cranium by the posterior part of the foramen 

 lacerum, in company with the vagus. For the space of about one inch 

 and a half it forms a common cord with that nerve. It then parts 

 company with the vagus, and passes backwards at the edge of the 

 rectus capitis anticus major muscle, where it is crossed superficially 

 by the occipital artery. It then turns round the wing of the atlas at 

 its most prominent point, and passes beneath the mastoido-humeralis 

 muscle, crossing the branches of the 2nd spinal nerve. Before it dis- 

 appears beneath the mastoido-humeralis it communicates with the 

 superior cervical ganglion, and gives a branch to the sterno-maxillaris 

 muscle. Its distribution in the neck has already been followed. 



The Sympathetic Nerve (Plate 32). The initial part of the cervical 

 coral is here seen passing back from the superior cervical ganglion. 

 After a course of a few inches it places itself beside the vagus, and 

 forms a common cord with it. 



The Superior Cervical Ganglion is placed on the gutteral pouch, 

 above the internal carotid artery. It is about half an inch in length, 

 fusiform in shape, and of a reddish-grey colour. Below it tapers into 



