48 HEAD AND NECK 



The four sensory nerves distributed mainly to the scalp 

 area behind the auricle are the great auricular and the lesser 

 occipital branches of the cervical plexus ; the greater occipital, 

 which is the medial division of the posterior ramus of the 

 second cervical nerve ; and the third occipital, not yet seen, 

 but which will be displayed when the body is turned on its 

 face. It lies medial to the greater occipital, and is the medial 

 division of the posterior ramus of the third cervical nerve. 

 The motor nerve distributed posterior to the auricle is the 

 posterior auricular branch of the facial nerve. 



The arteries distributed to the scalp are five in number on 

 each side ; they anastomose freely, and are derived, either 

 indirectly or directly, from the internal and external carotid 

 arteries. Three are distributed mainly anterior to, and two 

 posterior to the region of the auricle. The three anterior to 

 the auricle are the frontal and supra-orbital branches of the 

 ophthalmic branch of the internal carotid, which accompany 

 the supra-trochlear and supra-orbital nerves, respectively, and 

 the superficial temporal branch of the external carotid. The 

 superficial temporary artery divides into two main divisions, 

 an anterior division, which accompanies the temporal branches 

 of the facial nerve, and is usually a very tortuous vessel, and a 

 posterior division, which accompanies the auriculo-temporal 

 nerve, as it ascends, anterior to the auricle, towards the vertex 

 of the cranium. The two arteries posterior to the auricle are 

 both branches of the external carotid. They are the posterior 

 auricular, which accompanies the posterior auricular branch 

 of the facial nerve to the mastoid region and the posterior 

 part of the parietal region, and the occipital, which is distri- 

 buted to the occipital area and posterior part of the parietal 

 area (Figs. 15, 17, 51). 



The terminations of the veins which drain the blood from 

 the scalp are as follows. The frontal and supra-orbital veins 

 unite, at the medial border of the orbit, to form the angular 

 vein, which is the commencement of the anterior facial vein, 

 already dissected (p. 16). The blood it conveys passes 

 eventually to the internal jugular vein. The superficial 

 temporal vein accompanies the corresponding artery. It unites, 

 immediately above the posterior root of the zygoma, with the 

 middle temporal vein, which pierces the temporal fascia at 

 that point. The trunk formed by the union of the superficial 

 and middle temporal veins is the posterior facial vein, which 



