f. N. alveolaris inferior ([Fig. 154], d).—This passes toward the mandibular foramen, but before reaching it gives off a branch to the mylohyoid and digastric muscles. It then enters the foramen, passes through the mandibular canal, and gives numerous inferior dental branches to the teeth. At the mental foramen (or foramina) it passes out of the canal and divides into several mental nerves, to the chin, lower lip, and mucosa of the lower jaw.

g. N. lingualis ([Fig. 154], b).—The lingual nerve passes between the internal and external pterygoid muscles, and two or three millimeters from its origin it receives the chorda tympani nerve (c), a communicating branch from the facial (see [page 376]). It passes onto the ventral surface of the external pterygoid, thence onto the side of the tongue, beneath the mylohyoid. On the side of the tongue it divides into branches which enter the tongue and are distributed to its mucous membrane. One branch passes to the mucosa of the pharynx. Just before entering the tongue a branch is given off to the sublingual and submaxillary glands.

VI. N. abducens.

—The sixth nerve, the abducens, arises from the medulla, as already described ([Fig. 138], VI, and [page 347]). It passes into the orbit through the orbital fissure, then extends obliquely cranioventrad along the medial surface of the lateral rectus muscle ([Fig. 154], k). At about the middle of the length of the muscle it divides into two or three branches which enter at once into the lateral rectus and supply it.

VII. N. facialis

([Fig. 155]).—The seventh or facial nerve arises from the trapezium at the caudal margin of the pons, craniad of the origin of the eighth nerve, as described in the account of the brain ([Fig. 138], VII). It passes into the internal auditory meatus, traverses the facial canal through the petrous bone, and emerges at the stylomastoid foramen.

Within the facial canal the nerve bears an enlargement, the ganglion geniculi. It gives off within the canal a branch to the stapedius muscle, and the superficial petrosal and chorda tympani nerves.

The superficial petrosal (N. petrosus superficialis major) nerve passes into the hiatus facialis, through the canal which forms its continuation, and joins the sphenopalatine ganglion ([p. 373]).

[Fig. 155].—Superficial Nerves of the Face.