Trigeminal Nerve (CN V) – Anatomy and Pathways (Vocabulary Flashcards)

Vocabulary flashcards covering the anatomy, nuclei, ganglion, course, divisions, and clinical aspects of the trigeminal nerve.

Trigeminal Nerve (CN V)

The largest cranial nerve with both sensory and motor fibers; provides facial sensation and motor control of muscles of mastication.

Ophthalmic Nerve (V1)

Purely sensory branch of CN V; exits skull via the superior orbital fissure and supplies structures derived from the frontonasal prominence (eye, lacrimal gland, conjunctiva, nasal mucosa, forehead/skin).

Maxillary Nerve (V2)

Purely sensory branch of CN V; exits skull via the foramen rotundum; supplies midface structures including maxillary teeth and palate.

Mandibular Nerve (V3)

Mixed nerve (sensory and motor); exits skull via foramen ovale; supplies muscles of mastication and other first pharyngeal arch derivatives.

Trigeminal Nerve Nuclei

Four nuclei: main sensory nucleus, spinal nucleus, mesencephalic nucleus, and motor nucleus.

Main Sensory Nucleus

Located in the posterior part of the pons; processes touch/pressure from facial regions.

Spinal Nucleus

Extends from the medulla into the upper spinal cord; processes pain and temperature from the face.

Mesencephalic Nucleus

Contains proprioceptive (unipolar) neurons around the cerebral aqueduct; unique for bypassing the trigeminal ganglion to convey jaw proprioception.

Motor Nucleus of Trigeminal Nerve

Located in the pons near the main sensory nucleus; gives rise to the motor root and innervates muscles of mastication and related muscles (tensor tympani, tensor veli palatini, mylohyoid, anterior belly of digastric).

Trigeminal Ganglion (Gasserian Ganglion)

Sensory ganglion of CN V; made of pseudounipolar cells in Meckel's cave; gives rise to the sensory roots for V1–V3.

Meckel's Cave (Trigeminal Cave)

Dural recess in which the trigeminal ganglion sits near the apex of the petrous temporal bone.

Course of Trigeminal Nerve

Leaves the pons with a small motor root and a large sensory root; sensory root forms the ganglion in the middle cranial fossa; divisions arise from the ganglion.

Ophthalmic Nerve Pathway (V1)

Leaves the skull through the superior orbital fissure and enters the orbital cavity; purely sensory.

Maxillary Nerve Pathway (V2)

Leaves the skull through the foramen rotundum; purely sensory; supplies midface structures.

Mandibular Nerve Pathway (V3)

Leaves the skull through the foramen ovale; mixed nerve with motor and sensory fibers; supplies muscles of mastication and lower face.

Dermatomes of CN V Divisions

Each division (V1, V2, V3) innervates a distinct facial dermatome with little overlap between them.

Lingual Nerve

Branch of V3; carries general sensory information from the anterior two-thirds of the tongue.

Inferior Alveolar Nerve

Branch of V3; provides sensation to the lower teeth; gives rise to the mental nerve supplying the chin.

Superior Alveolar Nerves (V2)

Branches of V2 that supply the maxillary teeth; includes anterior, middle, and posterior superior alveolar nerves.

Proprioception of Jaw Muscles (Mesencephalic Nucleus)

Proprioceptive impulses from jaw muscles travel via the mesencephalic nucleus, bypassing the trigeminal ganglion.

Pain and Temperature Pathways (CN V)

Pain and temperature fibers terminate in the spinal nucleus of the trigeminal complex.

Touch and Pressure Pathways (CN V)

Touch/pressure fibers terminate in the main sensory nucleus of the trigeminal complex.

Trigeminal Neuralgia (Clinical)

Chronic facial pain syndrome affecting CN V; triggers by light touch or routine activities; more common in women and typically in people over 50; treatment includes surgery, injections, or medications.