DISSECTION OF THE HEAD AND NECK. 195 



capitis anticus major muscle, where it is crossed superfcially 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 disappears 

 beneath the mastoido-humeralis, it comnnmicates 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 Nervk (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 SuPERioK 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 

 the cervical cord, and above it tapers into the ascending oflFsets with the 

 internal carotid artery. Connecting branches unite the ganglion with 

 the 1st spinal nerve, and with the last four cranial nerves. Communi- 

 cations with some of the other cranial nerves are also established through 

 the carotid offsets of the ganglion. The distributory branches from the 

 ganglion pass to the adjoining vessels and the pharynx. Of the former 

 set, two branches accompany the internal carotid into the skull, and form 

 the carotid and cavernoiis plexuses. Other branches follow the external 

 carotid, and are continued on the branches of that artery. 



The 1st Cervical Nerve. The inferior primary branch of this 

 nerve descends through the antero-external foramen of the atlas, and 

 appears in company with the occipital vessels, between the rectus capitis 

 lateralis and the obliquus capitis superior. It passes towards the upper 

 extremity of the trachea, and splits into branches that enter the 

 terminal parts of the subscapulo-hyoid, sterno-hyoid, and sterno- 

 thjToid muscles. Beneath the atlas it gives branches to the anterior 

 and lateral straight muscles of the head ; and beyond that point it 

 furnishes a branch which supplies the thyro-hyoid muscle, and gives a 

 twig to join the hypoglossal nerve. It sends a communicating branch 

 to the superior cervical ganglion of the sympathetic. 



the tongue. 



Directions. — With the cavity of the mouth exposed as in Plate 30, 

 any poi-tions of food found in the cavity should be removed, and the 

 mucous membrane made clean. By moving the tongue about, the 

 following points will be observed. 



The inferior portion of the tongue lies free on the floor of mouth, from 

 which it can readily be drawn out. This part is two-sided, being flat- 

 tened from before to behind, and rounded at its extremity like a spatula. 

 The superior portion, on the other hand, cannot be displaced, and is 



