Cranial Nerve V and VII

Largest Two

Sensory (larger) -The nerve of the face, most of scalp, mouth, teeth and nasal cavity. -It contains proprioceptive fibers from the muscles involved in mastication (mandibular division) and possible also from the EOM (ophthalmic div.) Motor (smaller) Serves the muscles of mastication.

The trigeminal nerve emerges from the ventral surface of the pons. The fibers making up the sensory root originate from the unipolar cells in the trigeminal ganglion. The ganglion lies in a depression - middle cranial fossa-of the bone near the apex of the pterous part of the temporal brain.

I-In the pons, the trigeminal fibers take a dorso-medial course towards the principal sensory nucleus. -Before reaching the nucleus about 50% of the fibers divide into the ascending and descending branches, while the remaining 50% ascend or descend without division. -The spinal trigeminal tract is formed by descending fibers and terminates at the level of the C2, where the fibers synapse with cells making up the nucleus of the spinal trigeminal tract. -The nucleus of the spinal trigeminal tract is divided into discrete areas for the mandibular, maxillary and ophthalmic division of the trigeminal ganglion. -There is also a functional division of the nucleus into two levels.

-Touch -Pain and Temperature

-Large and heavily myelinated, will go to the mesencephalic nucleus, which is made up of a column of unipolar cells. -The peripheral branches of these neurons, it is believed convey proprioceptive impulses from muscles of mastication, muscles of the face and possible also from the teeth and EOMs to the mesencephalic nucleus. -These neurons are the only primary neurons in the body located in the CNS.

-Ovoid in shape and mainly composed of large multipolar cerve cells.

-Mandibular Nerve -Maxillary Nerve -Ophthalmic Nerve

-Largest division -Passes thru the Foramen Ovale -Supplies the teech , and gums of the mandible, the skin of the temporal region, part of the lower lip, part of the auricle, lower part of the face and the muscles of mastication and it also innervates mucous membrane of the anterior pre-sulcal part of the tongue and the floor of the mouth. -It may contain proprioceptor fibers along with somatosensory fibers.

-Intermediate division -Contains sensory fibers only, although along its course a modest number of postganglionic fibers links up with it. -After the maxillary nerve passes thru th Foramen Rotundum, its called the Infra-Orbital Nerve. -Contains many branches.

Middle Meningeal Nerve - Sensory to dura mater around the anterior half of the middle cranial fossa. Sphenopalatine ganglion branches (2)- connecting the infraorbital nerve with the peterygopalantine ganglion - but these contain autonomic nerve fibers from the facial nerve to the lacrimal gland. Superior, posterior, middle and anterior alveolar (dental) Ns - supplies the maxillary sinus, the teeth in the upper gum and cheek. Orbitocillary N. to the Ciliary Ganglion - Not always present but maxillary fibers will reach the eye via rami oculares if absent. Zygomatic N. - supplies the skin over the anterior part of the temporal region up to the later orbital margin and the skin over the zygomatic bone. The zygomatic nerve is a branch of the infraorbital nerve and passes thru the IOF. It then branches into the zygomaticofacial and zygomaticotemporal nerves, which enter the zygomatic canal in the zygomatic bone and emerge on the facial side of the bone to innervate the skin in that region. This nerve has been "alleged" to give off a communicating branch to the lacrimal nerve, this branch has never been demonstrated but it is thought to contain autonomic secretory fibers to the lacrimal gland. Infraorbital Nerve - Breaks up into a number of fine branches supplying the skin of the upper lip, the mucous memebrane of the upper gum, the lateral and lower part of the nose, and the skin and conj or the lower lid.

-smalles division -It runs forward in the lateral wall of the cavernous sinus enclosed in a separate sheath of dura. -CN III and CN IV pass above it.

Lacrimal Nerve Frontal Nerve Nasociliary Nerve

-The smallest branch -It passes into the orbit outside of the common tendinous annulus (of Zinn). -It has little to do with the lacrimal gland. -It innervates the upper lid and the superior portion of the conj and part of the forhead and temples.

-Large of the three branches. -Near the front of the orbit it divides into the supratrochlear and supraorbital nerve. -Supratrochlear supplies the skin of the forehead and the upper lid and the conj. -They have overlapping fields.