Cranial Nerves VI - XII

CN VI: Abducens Nerve

  • The abducens nerve is a small motor nerve.
  • It innervates the lateral rectus muscle, an extrinsic eye muscle.

CN VII: Facial Nerve

  • The facial nerve is a mixed nerve with multiple functions.
  • Motor function: Innervates the muscles of facial expression.
  • Sensory function: Provides taste sensation from the anterior two-thirds of the tongue.
  • Autonomic function: Innervates the lacrimal glands (tear production), and salivary glands (mucus and saliva production).
  • Sensory function: Provides sensation from part of the face and mouth.

CN VIII: Vestibulocochlear Nerve

  • The vestibulocochlear nerve is a sensory nerve.
  • It innervates the structures of the inner ear.
  • Functions: Provides the senses of hearing and equilibrium.

CN IX: Glossopharyngeal Nerve

  • The glossopharyngeal nerve is a small mixed nerve.
  • Motor function: Innervates muscles of the pharynx (throat) involved in swallowing.
  • Sensory function: Provides taste sensation from the posterior one-third of the tongue.

CN X: Vagus Nerve

  • The vagus nerve is a mixed nerve.
  • It is the only cranial nerve that "wanders" outside of the head and neck.
  • "Vagus" means "wanderer."
  • Sensory function (head and neck): Provides some sensory innervation from the skin of the head and the pharynx.
  • Motor function (head and neck): Innervates muscles involved in speech and swallowing and certain salivary glands.
  • Outside the head and neck: Innervates most of the thoracic and abdominal viscera.
  • Main nerve of the parasympathetic nervous system.

CN XI: Accessory Nerve

  • The accessory nerve is unique because it has both cranial and spinal components.
  • Cranial component: Originates from the brainstem.
  • Spinal component: Originates from the spinal cord.
  • Motor function: Innervates muscles that move the head and the neck, such as the trapezius and sternocleidomastoid muscles.

CN XII: Hypoglossal Nerve

  • The hypoglossal nerve is a small motor nerve.
  • It innervates the muscles that move the tongue.
  • Important note: The hypoglossal nerve moves the tongue but does not provide any taste sensation to the tongue.

Mnemonic for Cranial Nerves

  • A mnemonic is provided to help remember the order of the cranial nerves.
  • Mnemonic: "Oh, Once One Takes The Anatomy Final Very Good Vacations Are Happening"
  • Olfactory (CN I)
  • Optic (CN II)
  • Oculomotor (CN III)
  • Trochlear (CN IV)
  • Trigeminal (CN V)
  • Abducens (CN VI)
  • Facial (CN VII)
  • Vestibulocochlear (CN VIII)
  • Glossopharyngeal (CN IX)
  • Vagus (CN X)
  • Accessory (CN XI)
  • Hypoglossal (CN XII)
  • Additional tip: Remember one nose (CN I, olfactory) and two eyes (CN II, optic).