Facial Nerve (Cn Vii)

Front 1

What is the facial nerve?

Back 1

CN VII
It is said to be the nerve to the muscles of facial expression (mimetic muscles), but has other functions as well.
Passes through the facial canal.

Front 2

What are the components of the facial nerve?

Back 2

-Special visceral efferent (SVE) motor fibers
-General visceral efferent (GVE) motor fibers
-Special visceral afferent (SVA) fibers
-General somatic afferent (GSA)

Front 3

What are the special visceral efferent (SVE) motor fibers?

Back 3

VOLUNTARY CONTROL (has nothing to do with ANS). Motor fibers that innervate the muscles of facial expression. Their nerve cell bodies are in the motor nucleus of the facial nerve.
(Think of the oral cavity as a hollow organ associated with the digestive system)

Front 4

What are the visceral efferent (GVE) motor fibers?

Back 4

Provide parasympathetic innervation to the lacrimal gland, mucosa of the palate and nasal cavities, and the submandibular and sublingual salivary glands.

Front 5

Where do the preganglionic nerve fibers of the GVE motor fibers synapse?

Back 5

In two different parasympathetic ganglia:
-pterygopalatine ganglion
-submandibular ganglion

Front 6

Where do the postganglionic nerve fibers from the pterygopalatine ganglion travel to?

Back 6

-lacrimal glands
-nasal mucosa
-palate

Front 7

Where do the postganglionic nerve fibers from the submandibular ganglion travel to?

Back 7

-sublingual salivary gland
-submandibular salivary gland

Front 8

What are the special visceral afferent (SVA) fibers?

Back 8

Fibers for taste (from the anterior 2/3 of the tongue) are present in the chorda tympani branch of the facial nerve.
(Think special senses; hearing, taste, smell)

Front 9

What are the general somatic afferent (GSA) fibers?

Back 9

Bring cutaneous innervation from a portion of the external auditory meatus and auricle. Proprioceptive fibers also provide for "position sense" for the facial muscles. Feel pain, temperature, touch, and pressure.

Front 10

Where is the motor nucleus of the facial nerve?

Back 10

The pons.

Front 11

How does the facial nerve exit the cranial cavity?

Back 11

Via the internal acoustic meatus, where it makes a sharp turn and enters the facial canal.

Front 12

What are the branches of the facial nerve within the facial canal?

Back 12

-the greater petrosal nerve
-nerve to the stapedius muscle
-chorda tympani nerve

Front 13

Describe the chorda tympani nerve?

Back 13

Passes through the middle ear, where it joins with the lingual nerve (CN V3). Distributed to the submandibular and sublingual glands. Also contains SVA fibers which bring taste from the anterior 2/3s of the tongue.

Front 14

What are the branches of the facial nerve external to the skull?

Back 14

-sends a sensory branch (GSA) to the external auditory meatus and the auricle
-terminal branches of the facial nerve supplying the muscles of facial expression

Front 15

What are the terminal branches of the facial nerve supplying the muscles of facial expression?

Back 15

-temporal branches
-zygomatic branches
-buccal branches
-mandibular branch
-cervical branch
-posterior auricular branch

Front 16

What does the temporal branch of the facial nerve supply?

Back 16

All of the superficial muscles above it, including the frontal belly of the occipitofrontalis, the corrugator supercilii, the orbicularis oculi and the anterior and superior auricular muscles.

Front 17

What does the zygomatic branch of the facial nerve supply?

Back 17

The muscles in the infraorbital area including the orbicularis oculi and all muscles associated with the upper lip, external nares, and part of the buccinator muscle.

Front 18

What does the buccal branch of the facial nerve supply?

Back 18

The buccinator and levators of the upper lip and angle of the mouth, depressors of the lower lip and angle of the mouth (both of which are also innvervated by the mandibular branch of CN VII).

Front 19

What does the mandibular branch of the facial nerve supply?

Back 19

Muscles of the lower lip and chin.

Front 20

What does the cervical branch of the facial nerve supply?

Back 20

The platysma.

Front 21

What does the posterior auricular branch of the facial nerve supply?

Back 21

Auricular muscles (which can only move the auricle in some people).

Front 22

What happens if there is a lesion of the motor nucleus of the facial nerve?

Back 22

Produces ipsilateral paralysis of the muscles of facial expression and eventually muscle atrophy as well. Can result from chilling of the face, middle ear infections, tumor and fractures (account for 75% of facial nerve Bell's palsy).

Front 23

What causes weakness of facial muscles?

Back 23

Results from injury to the branches of the facial nerve. Injury does not cause complete paralysis, b/c of the overlapping distribution of the branches.