Anatomy of the face & parotid region: P2
Briefly explain the intracranial path of the facial nerve?
1) comprised of 4 nuclei. 2) Arises from pons and exits as 2 roots 3.) 2 roots travel through Internal acoustic (auditory) meatus (temporal bone) 4.) enter facial canal 5) 2 roots fuse to form the facial nerve in the facial canal 6) Facial nerve forms Geniculate ganglion 7) Nerve gives rise to 3 branches -Greater petrosal nerve -Nerve to stapedius -Chorda tympani nerve
What is the extracranial path of the facial nerve?
1. CN VII emerges from the cranium via the stylomastoid foramen 2. Gives off posterior auricular branch 3. Enters the parotid gland 4. Gives rise to the 5 terminal motor branches:
What 3 important events occur in the facial canal in order?
1. The two roots fuse to form the facial nerve. 2. Next, the nerve forms the geniculate ganglion 3. Lastly, the nerve gives rise to: -Greater petrosal nerve -Nerve to stapedius -Chorda tympani nerve
What structures do the facial nerve innervate? >Motor (SVE) >Special sensory (SVA) >Somatic sensory (GSA) >Visceral Motor (GVE)
>Motor (SVE): -Muscles of facial expression >Special sensory (SVA): -Anterior 2/3rds of tongue & soft palate >Somatic sensory (GSA): -Small area of skin of auricle (auditory canal) -Opening of external acoustic meatus >Visceral Motor (GVE): Carries secretomotor (parasympathetic) fibers -Submandibular and sublingual glands (salivary glands)
What is hyperacusis?
A type of reduced tolerance to sound. People with hyperacusis often find ordinary noises too loud
CN VII is associated with which foramen(a)? (CHOOSE ALL THAT APPLY) A. Internal auditory meatus B. External auditory meatus C. Foramen spinosum D. Stylomastoid foramen
A. Internal auditory meatus & D. Stylomastoid foramen
What information does the geniculate ganglion carry?
Both sensory & motor
ID #5
Cervical nerve
Which is not a point of overlap between CN VII and CN V? A. Special sensory to the tongue B. Modulation of loud noises in the ear C. Secretomotor innervation to salivary glands D. Innervation of muscles of facial expression
D. Innervation of muscles of facial expression
Where can you find nerve to stapedius?
Depths of the temporal bone
Where does the facial nerve (CN VII) emerge from? how many divisions does it have
Emerges at the junction of the pons and medulla as 2 divisions
Where is the stylomastoid foramen?
Exit located just posterior to the styloid process of the temporal bone.
Where do the 2 roots go after leaving the internal acoustic meatus?
Facial canal ("Z "shaped structure)
What is the stapedius muscle innervated by?
Nerve to the stapedius, branch of facial nerve (CN VII)cc
Which one is more medial? The opening for the submandibular duct or the opening fo the sublingual duct?
Opening for the submandibular duct
The internal acoustic auditory meatus is part of what bone?
Temporal bone
What are the attachment of the Stapedius muscle?
Tendon of the stapedius enters the tympanic cavity by emerging from a pinpoint foramen in the apex of the eminence and inserts on the neck of the stapes bone.
What is the name of the nerve that gives general sensory to the ear?
Posterior auricular branch AKA Nerve to intermediate
What does the Greater Petrosal nerve innervate?
Preganglionic parasympathetic innervation to pterygopalatine ganglion
>Is the Chorda Tympani nerve sensory or motor? >What information does it carry?
Sensory: Carries taste from anterior 2/3rds of tongue • Joins the lingual nerve in the infratemporal fossa (branch ofV3) Motor: Carries secretomotor (parasympathetic) fibers to submandibular ganglion for the submandibular and sublingual glands • Fibers travel on blood vessels to the gland, along with sympathetic fibers
Where does the facial nerve arise from and exit as?
The nerve arises in the pons and exits as two roots: -Large motor root -Small sensory root
Where do the 2 roots of the facial nerve travel through?
Travel through the internal acoustic[auditory] meatus, a 1 cm long opening in the petrous part of the temporal bone. Here, they are in very close proximity to the inner ear.
Which 2 cranial nerves overlap each other?
Trigeminal & Fascial nerve
ID #2
Zygomatic nerve
What are the 5 terminal motor branches of the fascial nerve?
•Temporal •Zygomatic •Buccal •Marginal mandibular •Cervical "Two Zebras Bit My Cheek"
Where can you find the stapedius muscle?
Inside the pyramidal eminence A hollow, cone-shaped prominence on the posterior wall of the tympanic cavity
Which muscle is NOT innervated by CN VII? A) Oribicularis oris B) Buccinator C) Masseter D) Mentalis
Masseter
What are the branches of the fascial artery?
-Angular a. -Lateral nasal a. -Superior labial a -Inferior labial a. SAIL
What are some causes of Hyperacusis?
-Head trauma -History of ear infections -Surgeries on ear or brain -Exposure to loud sounds -Depression -Sensitizing drugs -TMJ -Aging -Bell's Palsy -Lyme Disease
What happens to the Greater petrosal nerve after it innervates the pterygopalatine ganglion?
-Joins the deep petrosal nerve (sympathetic) & forms part of a chain of nerves that provide secretomotor innervation
After the greater petrosal nerve joins with the deep pertrosal nerve, what structures do they provide secretomotor innervation to?
-Lacrimal gland -Mucosal glands -Nasal cavity & palate
What is the names of the 4 nuclei of the facial
-Main motor nucleus (aka facial nucleus) SVE -Superior salivary nucleus (GVE)-Parasympathetic -Spinal trigeminal nucleus (GSE) -Solitary nucleus (SVA)
What are the bones of the auditory ossicles?
-Malleus -Incus -Stapes
What are the functional components/information the facial nerve (CN VII) carries?
-Motor (SVE) -Special sensory (taste) (SVA) -General Somatic sensory (GSA) -General Visceral Motor (GVE)
The somatic motor of the facial nerve innervates what structures?
-Muscles of facial expression -Auricular muscles -Posterior belly of digastric, stylohyoid & stapedius muscles
What are the salivary glands of the face?
-Parotid -Submandibular -Sublingual -Small accessory salivary glands
What are the 2 divisions of the facial nerve? What information does it carry?
-Primary root (aka facial nerve proper) MOTOR fibers -Intermediate nerve: SENSORY + PARASYMPATHETIC fibers
What are the actions of the stapedius muscle?
-Pulls the stapes bone posteriorly there by reducing the oscillatory range -Prevents excessive movement of the stapes -Helps dampen sound
What are the vessels of the face (branchs of external carotid artery)
-Superficial temporal artery -Fascial artery Image: * = branched of Internal carotid. All other labeled arteries are from external carotid
What are the 2 arteries that branch off of the Internal carotid artery?
-Supratrochlear a. -Supraorbital a.
What 2 muscles are associated with Hyperacusis?
-Tensor Tympani -Stapedius muscle
Name the artery that branches off of superficial temporal artery:
-Transverse fascial artery
What are the functions of the salivary glands of the face as a whole?
Functions: -Keeps mucous membrane of the mouth moist -Lubricates the food during mastication -Begins the digestion of starches -Serves as an intrinsic "mouthwash" -Significant role in prevention of tooth decay & in the ability to taste
Where are the sensory cell bodies for taste located?
Geniculate ganglion
Parasympathetic-preganglionic fibers of CN V1 are carried in what nerve before synapsing at the pterygopalatine ganglion?
Greater petrosal nerve
After the intercranial path, where does the fascial nerve exit the facial canal (and the cranium)?
INSERT IMAGE Stylomastoid foramen
