Cranial Nerves VII-XII

Pure Sensory

CN VIII (Vestibulocochlear)

Pure Motor

CN XI (Accessory) and CN XII (Hypoglossal)

Mixed (Sensory and Motor)

CN VII (Facial), CN IX (Glossopharyngeal), and CN X (Vagus)

Where do CN VII and CN VIII emerge?

At the cerebellopontine angle in the pontomedullary junction

Where do CN VII and CN VIII exit the skull?

Internal acoustic meatus

Where do CN IX, X, and CN XI emerge?

Posterior to the inferior olive

Where do CN IX, X and XI exit?

Jugular foramen

Which cranial nerves are in the Postolivary Sulcus (medulla)?

CN IX, X and XI

Where does CN XIII emerge?

Anterior to the olive

Where does CN XIII exit?

Hypoglossal canal

Which cranial nerves are in the Preolivary Sulcus (medulla)?

CN XIII

Fiber Types of CN VII (Facial Nerve)

SVE (Brachial Motor)
GVE
SVA
GSA

Where does CN VII SVE emerge?

Facial motor nucleus

What does the SVE of CN VII innervate?

Muscles of facial expression, occipitofrontalis, platysma, stapedius, stylohyoid, and posterior belly of the digastric muscle

Where does the GVE of CN VII emerge?

Superior salivatory nucleus and lacrimatory nucleus to supply the secretomotor fibers to the submandibular, sublingual and lacrimal glands

Where does the SVA (Special Sensory) fibers of CN VII emerge?

Projects to gustatory portion of nucleus of solitary tract (NTS), carrying taste from anterior 2/3 of tongue

Where do the GSA fibers of CN VII emerge?

Projects to spinal trigeminal nucleus, carrying sensation from a small area of skin on the external ear

Clinical Lesion of LMN (Bell’s Palsy/Nerve Lesion)

Causes complete paralysis of upper and lower facial muscles on the ipsilateral side (loss of forehead wrinkling, inability to close the eye/blink, drooping mouth, hyperacusis due to loss of stapedius, dry eye, dry mouth, and loss of taste on anterior 2/3 of tongue

UMN Lesion (Corticobulbar Tract Stroke)

Paralysis affects only the lower half on the contralateral face, sparing the upper forehead because the upper facial motor pool receives bilateral corticobulbar drive

Fiber type of Vestibulocochlear

SSA (Special Somatic Afferent)

Cochlear Division Pathway

Sound—>Cochlea—>Cochlear Nucleus—>Superior olive (sound localization)—>inferior colliculus—>Medial Geniculate Nucleus (MGN of thalamus)—>Primary Auditory cortex (temporal lobe)