trigeminal nerve (CN V)

Introduction

Somatic motor & somatic sensory functions. All of the motor & sensory fibers of CN 5 enter the brainstem at the level of the pons

Afferents

Sensory nucleus of CN 5

• very long, extending from the rostral pons into the medulla oblongata & becoming continuous with the posterior horn of the spinal cord
• spinal nucleus of CN 5
  • pain & temperature
  • spinal tract of CN 5 sends fibers caudal from the pons to the brainstem before relaying sensory information of pain & temperature
• main sensory nucleus of CN 5
  • located in pons & medulla
  • light touch
• mesencephalic nucleus of CN 5
  • located in midbrain
  • proprioception
• fibers sent to the thalamus via the trigeminal lemniscus
• primary sensory neurons of CN 5 have cell bodies in the trigeminal ganglion
• the sensory distribution of CN 5 is like that of a face mask

Efferents

Motor nucleus of CN 5

• small round nucleus confined to pons anterior & lateral relative to other somatic motor nuclei in the brainstem
• nerve fibers originating in the motor nucleus of CN 5 innervates the muscles of mastication, i.e. masseter

Branches

Three branches of CN 5

• ophthalmic branch: innervates:
  • forehead
  • top of head
  • around eyes
  • top of nose
• maxillary branch: innervates:
  • cheeks
  • temporal region
  • lower portion of nose
  • upper lip
• mandibular branch: innervates:
  • chin
  • jaw
  • lower lip

More general terms

• cranial nerve

Additional terms

• mandibular nerve (CN V-3)
• maxillary nerve (CN V-2)
• ophthalmic nerve (CN V-1)
• trigeminal motor nucleus (motor nucleus of CN V)
• trigeminal neuralgia (tic douloureux)
• trigeminal sensory nucleus