SURFACE MARKINGS OF SPECIAL REGIONS OF HEAD AND NECK 1295 



to the angle of the mouth, thence to the ala of the nose and upward to the medial 

 commissure of the eye (Fig. 1200). 



Trigeminal Nerve. Terminal branches of this nerve, viz., the supraorbital branch 

 of the ophthalmic, the infraorbitalof the maxillary, and the mental of the mandibular 

 emerge from corresponding foramina on the face (Fig. 1200). The supraorbital 

 foramen is situated at the junction of the medial and intermediate thirds of the 

 supraorbital margin. A line drawn from this foramen to the lower border of the 

 mandible, through the interval between the two lower premolar teeth, passes over 

 the infraorbital and mental foramina; the former lies about 1 cm. below the margin 

 of the orbit, \vhile the latter varies in position according to the age of the individual; 

 in the adult it is midway between the upper and lower borders of the mandible, 

 in the child it is nearer the lower border, while in the edentulous jaw of old age 

 it is close to the upper margin. 



.xVSSRHi- 



jgpfj Frontal sinus 



Line of nasolacrimal 

 duct 



Maxillary sinus 



FIG. 1199. Outline of bones of face, showing position of 

 air sinuses. 



FIG. 1200. Outline of side of face, showing chief 

 surface markings. 





The position of the sphenopalatine ganglion is indicated from the side by a 

 point on the upper border of the zygomatic arch, 6 mm. from the margin of the 

 zygomatic bone. 



Parotid Gland (Fig. 1200). The upper border of the parotid gland corresponds to 

 the posterior two-thirds of the lower border of the zygomatic arch; the posterior 

 border to the front of the external acoustic meatus, the mastoid process, and- the 

 anterior border of Sternocleidomastoideus. The inferior border is indicated by a 

 line from the tip of the mastoid process to the junction of the body and greater 

 cornu of the hyoid bone. In front, the anterior border extends for a variable dis- 

 tance on the superficial surface of the Masseter. The surface marking for the parotid 

 duct is a line draw r n across the face about a finger's breadth below r the zygomatic 

 arch, i. e., from the lower margin of the concha to midway between the red margin 



