3. N. mandibularis.—The third division of the fifth, the mandibular nerve, takes origin by a strong root from the semilunar (or Gasserian) ganglion, and receives also after separating from the ganglion the smaller ventral root (portio minor) of the fifth nerve. The root from the ganglion is sensory; the smaller root is motor, so that the mandibular nerve is both sensory and motor. The nerve passes through the foramen ovale, and sends off at once the following branches:
a. N. auriculotemporalis ([Figs. 154] and [155], n).—This passes dorsad between the cartilaginous auditory meatus and the zygomatic process of the temporal bone ([Fig. 154], n), emerges at the caudal border of the masseter muscle ([Fig. 155], n), and divides into two chief branches. One, the auricular branch, passes along the cranial side of the external ear and is distributed to its integument. The other, the temporal branch, passes along the zygomatic arch, gives branches to the temporal muscle and to the skin, follows the zygomatic arch almost to the angle of the mouth, and anastomoses with the superior buccal branch of the facial ([Fig. 155], k).
b. N. temporalis profundus.—One or more large branches passing mediad of the zygomatic arch to the temporal muscle.
c. N. massetericus.—The masseteric nerve passes dorsocraniad to the masseter muscle.
d. N. pterygoideus.—One or more pterygoid branches pass to the pterygoid muscles. A small twig from the nerve to the internal pterygoid passes into the tympanic cavity and supplies the tensor tympani muscle.
e. N. buccinatorius ([Fig. 154], e).—This passes craniad along the dorsolateral surface of the pterygoid muscles ([Fig. 154], 8) to the angle of the mouth. Here it divides into branches to the masseter muscle, the mucosa of the mouth, and to the lips.
[Fig. 154].—Dissection showing a Number of the Cranial Nerves.
![[Fig. 154]](#3418956513767812439_illo374lg.jpg.id-3584782877305376119.wrap-0.html.html){kind=link}
The mandible and zygomatic arch have been cut and removed; the temporal and internal pterygoid muscles are also removed. a, N. hypoglossus; b, N. lingualis; c, N. chorda tympani; d, N. alveolaris inferior (cut); e, N. buccinatorius; f, Nn. infraorbitales; g, N. sphenopalatinus; h, branch of N. oculomotorius; i, N. zygomaticus; j, N. lachrymalis; k, N. abducens; l, N. trochlearis; m, N. frontalis; n, N. auriculotemporalis. 1, cut end of zygomatic process of temporal; 2, tympanic bulla; 3, M. digastricus; 4, M. constrictor pharyngis medius; 5, M. hyoglossus; 6, M. genioglossus; 7, M. geniohyoideus; 8, M. pterygoideus externus (cut); 9, cut cranial end of zygomatic arch; 10, mandible (cut); 11, lachrymal gland.
After giving off the above branches the mandibular nerve passes three or four millimeters laterad along the root of the zygomatic process of the temporal bone, and divides into two large branches, the inferior alveolar (or dental) nerve (d) and the lingual nerve (b).