THE HEAD AND NECK H^S 



THE FACE. 



Landmarks. — ^The nasal eminence or glabella of the frontal bone 

 can be felt just above the root of the nose, and extending outwards 

 from it on either side is the superciliary ridge, behind the inner part 

 of which is the corresponding frontal air-sinus. Below the super- 

 ciliary ridge the supra-orbital arch can readily be felt, and at the 

 junction of its inner third and outer two-thirds is the supra-orbital 

 notch, or foramen, for the passage of the supra-orbital ner\-e and 

 artery. A line drawn from the position of the supra-orbital notch 

 to the base of the inferior maxilla, in such a manner as to pass 

 between the lower bicuspid teeth, crosses in succession the infra- 

 orbital and mental foramina. The infra-orbital foramen lies in 

 this line at a point about ^ inch below the infra-orbital margin, and 

 it indicates the exit of the infra-orbital nerve and artery from the 

 infra-orbital canal. The mental foramen in the adult lies midway 

 between the alveolar and basilar borders of the inferior maxilla, 

 and it indicates the exit of the mental nerve and artery from the 

 inferior dental canal. 



In line with the tragus of the auricle the zygomatic arch can be 

 felt, and leading back%vards from it above the orifice of the meatus 

 auditorius extemus is the posterior root of the zygoma. This 

 root is continued into the supramastoid crest, which corresponds 

 to the level of the tegmen antri. In connection with the supra- 

 mastoid crest it is important to note the position of the suprameatal 

 triangle of Macewen. This triangle is bounded above by the supra- 

 mastoid crest, below by the postero-superior part of the meatus 

 auditorius extemus, and behind by a vertical line cormecting the 

 upper and lower boundaries, this line being continuous with the 

 posterior part of the meatus auditorius extemus. 



The superficial temporal artery and auriculo-temporal nerve lie 

 directly in front of the tragus, the division of the artery into its 

 anterior and posterior branches taking place about the level of the 

 upper part of the auricle. The anterior branch of the artery lies 

 nearly an inch above the external angular process of the frontal 

 bone, and the posterior branch about an inch above the upper part 

 of the auricle. 



The parotid gland is situated in front of the auricle. It is 

 limited above by the zygoma, behind by the auricle, and interiorly it 

 extends for a limited distance into the digastric triangle of the neck. 

 Anteriorly it extends for a short distance over the masseter muscle, 

 and Stensen's duct issues from its anterior border. The course of 

 this duct may be indicated by a line drawn from the incisura inter- 

 tragica, or from the junction of the lobule and cartilage of the auricle, 

 to a point midway between the nostril and the red margin of the 

 upper lip. About the middle third of this line corresponds to the 

 duct. Above it is the transverse facial artery, and below it are 

 the infra-orbital branches of the facial nerve. The course of the 



