44 ANATOMY OF THE HEAD AND NECK. 



DISSECTION VI. 



EXTERNAL CAROTID ARTERY. 



The dissection of the external carotid artery is to be undertaken 

 by following out from the main trunk those branches which have 

 been partly dissected, in preparing the parts already examined, as 

 well as those which have not yet been alluded to, but are now to be 

 described. 



Opposite the upper border of the thyroid cartilage or a 

 little higher, the common carotid artery divides into two 

 large trunks, the external and internal carotid branches. 

 At first, the external carotid lies upon the inner side, 

 nearer the middle line of the body than the internal 

 carotid, their distinctive names having reference, not to 

 their relative position, but to their destination to parts 

 nearer or more remote from the surface ; it soon, however, 

 becomes superficial to the internal carotid and divides into 

 numerous branches. The internal caroiid may be distin- 

 guished b} T a peculiar fusiform dilatation at its commence- 

 ment ; sometimes this dilatation is very marked, forming 

 an abrupt rounded distension of the vessel. 



The external carotid is crossed by the stylo-hyoid and 

 digastricus muscles, and by the hypoglossal nerve, and is 

 imbedded for a part of its course in the parotid gland ; 

 between the angle of the jaw and the mastoid process it 

 terminates by dividing into the internal maxillary and 

 temporal arteries. Its branches are the 



Superior thyroid, Posterior auricular, 



Lingual, Ascending pharyngeal, 



Facial, Temporal, 



Occipital, Internal maxillary. 



The superior thyroid artery descends, passing beneath the omo-hyoid, 

 sterno-thyroid, and sterno-hyoid muscles to the thyroid body, to the 

 superficial surface of which it is distributed, and where it anastomoses 

 with its fellow of the opposite side. It sends offsets to the hyoid region 

 and larynx, under the name of superior hyoid and inferior larynyeal 

 branches. 



The lingual artery passes obliquely forward beneath the hyo-glossus 

 muscle. In that part of its course which is parallel to the os hyoides, 

 the hyo-glbssus muscle separates it from the hypoglossal nerve, the 

 latter being the more superficial. The lingual artery supplies the 

 tongue, and is continued forward to the tip of that organ under the 

 name of the ranine artery. 



The facial artery arises above the lingual, sometimes from a com- 



