L7: Facial Nerve

Question 1

Peripheral Nerves unique to Cranial Nerves?

• Special visceral afferent (SVA): ____________
• Special somatic afferent (SSA): ____________
• Special visceral efferent (SVE): ____________

Answer 1

• Special visceral afferent (SVA): taste, smell
• Special somatic afferent (SSA): vision, balance, hearing
• Special visceral efferent (SVE)- (branchial efferent) to muscles derived from branchial arches

Question 2

Which cranial nerves is the nucleus solitarius involved with?

Answer 2

CN VII, IX, X

Question 3

Answer 3

Question 4

Functions of the Facial Nerve?

• SVEs?
• GVEs?
• SVAs?
• GSAs?

Answer 4

Question 5

Answer 5

Question 6

Facial Nerve

Answer 6

Facial Nerve

Question 7

Answer 7

Question 8

Facial Nerve

Answer 8

Facial Nerve

Question 9

Answer 9

Question 10

Facial Nerve Intracranial Course

• Facial nerve exits brainstem lateral to CNVI at _______________
• It then courses through _____________ (with CNVIII) towards _______________ (___________ of temporal bone)
• Beyond the IAM, CNVII forms a bend where ______________ is located
• Nerve courses posteriorly in facial canal towards _____________________

Answer 10

• Facial nerve exits brainstem lateral to CNVI at pontomedullary junction
• It then courses through subarachnoid space (with CNVIII) towards internal acoustic meatus (petrous part of temporal bone)
• Beyond the IAM, CNVII forms a bend (genu) where geniculate ganglion is located
• Nerve courses posteriorly in facial canal towards stylomastoid foramen

Question 11

Main ganglion for all sensory and special sensory CN7 functions?

Answer 11

Geniculate Ganglion

Question 12

Innervates lacrimal and nasal/palatine glands, via sphenopalatine ganglion?

Answer 12

Greater Petrosal Nerve

Question 13

Transmits taste sensation + secretomotor supply to salivary glands (sublingual/submandibular)

Answer 13

Chorda Tympani

(CNIX Innervates Parotid Gland)

Question 14

Intracranial Components of Facial Nerve? (4)

Answer 14

Question 15

Brachiomotor supply of the Facial nerve? (5)

Where does this supply arise?

Answer 15

• Muscles of facial expression (2nd branchial arch)
• Stapedius
• Occipitalis (via post. auricular branch)
• Posterior belly of digastric
• Stylohyoid

Most supply arises after facial nerve exits Stylomastoid Foramen

Question 16

Difference in facial Nerve (CNVII) supply to the upper and lower face?

Answer 16

Upper (bilateral)

Lower (contralateral only)

Question 17

Facial Nerve Parasympathetic (GVE) Innervations?

Nerves that innervate each gland?

Pre-ganglionic neurons arise in the ____________________________

Answer 17

• Lacrimal, Nasal + Palatine glands via greater Petrosal Nerve
• Sublingual & Submandibular (salivary) glands via Chorda Tympani

Pre-ganglionic neurons arise in the Superior Salivatory Nucleus

Question 18

SVA of Facial Nerve? Where do its cell bodies arise and travel?

Answer 18

TASTE

• Cell bodies in Geniculate Ganglion
• Afferents carried via lingual nerve & chorda tympani towards Nucleus Solitarius

Question 19

Testing for CNVII?

Answer 19

Ask pt to make facial expressions: see if there are any kind of abnormalities

Question 20

What does a lower motor lesion of branches of the facial nerve lead to?

Answer 20

Bell’s Palsy

*Upper Motor Lesions spare upper part of face as supplied

Question 21

Answer 21