Henry Gray (18251861). Anatomy of the Human Body. 1918.
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 infraorbital of 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, while 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.
FIG. 1199 Outline of bones of face, showing position of air sinuses. (See enlarged image)
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 distance on the superficial surface of the Masseter. The surface marking for the parotid duct is a line drawn across the face about a fingers breadth below the zygomatic arch, i. e., from the lower margin of the concha to midway between the red margin