DISSECTION OP THE HEAD AND NECK. 199 



vmder the occipital ; and above the first part of the trachea it 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 wliere 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 oBsophagus. 



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 miiscles. 



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 vaguSj aud passes backwards at the edge of the rect>is 

 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 spmal nerve. Before it disappears 

 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 

 cord 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 guttural 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 



