Facial Nerve Disorders Flashcards
What is somatic motor?
Innervation of skeletal muscles
What is visceral motor?
Innervation of smooth muscles
What is visceral sensory?
Sensation from the viscera (includes taste and smell as they are associated with the digestive tract)
What is somatic sensory?
Sensation from sensory organs, skin, skeletal muscles, and connective tissue
What are the sensory nerves?
Olfactory
Optic
Vestibulocochlear
What are the motor nerves?
Oculomotor
Trochlear
Abducens
Accessory
Hypoglossal
What are the mixed nerves?
Trigeminal
Facial
Glossopharyngeal
Vagus
Does the facial nerve have somatic motor, visceral motor, visceral sensory, and somatic sensory?
Yes
What is the somatic motor innervation of the facial nerve?
Muscles of facial expression (furrowing the forehead, raising eyebrows, etc.)
Postauricular muscle
Stapedius muscle (MEMR)
What is the postauricular muscle involved in?
Used to be involved in ear twitching like a rabbit
What is the visceral motor innervation of the facial nerve?
Lacrimal (tear ducts) and salivary glands (submandibular and sublingual)
Paralysis can result in a lack of tears
What is the visceral sensory innervation of the facial nerve?
Taste in the anterior 2/3 of the tongue (chorda tympani nerve)
What is the somatic sensory innervation of the facial nerve?
Posterior EAC, concha, ear lobe, and deep parts of the face
What is the origin of the facial nerve?
Facial motor nucleus in the anterior pons
What is the insertion of the facial nerve?
Muscles of facial expression and the stapedius muscle
Is the facial nerve a mixed nerve that is derived from the second pharyngeal arch?
Yes
Does the facial nerve have multiple segments to it?
Yes
What is the intracranial segment of the facial nerve?
Arises from the facial motor nucleus in the anterior pons
Exits the brainstem through the CPA
Goes to the internal auditory canal
Once the facial nerve exits the brainstem, how close does it lie to the superior vestibular nerve and the cochlear nerve?
1.5 mm
Does the AICA provide blood supply to the facial nerve after it exits the brainstem?
Yes
It runs between the VII and VIII nerves
What is the chorda tympani?
It is a branch of the facial nerve
It lies between VII and VIII in the IAC
After entering the IAC, where does the facial nerve go?
It travels 8 to 10 mm to the meatal foramen (opening of the IAC)
In the meatal foramen, does the facial nerve and the facial canal narrow?
Yes
This is a common site for facial nerve entrapment and associated disorders
Where is the facial canal?
It extends between the IAC and the stylomastoid foramen
Does the facial nerve have an intratemporal portion?
Yes
What are the three segments that fall in the intratemporal portion?
Labyrinthine segment
Tympanic segment
Mastoid segment
What is the labyrinthine segment?
Passes through narrowest part of the fallopian canal
Common site of pathology (temporal bone fractures and bells palsy)
What is the tympanic segment?
Forms the superior aspect of the oval window niche
Facial nerve is readily injured here in pathologic processes and during ME surgery
What is the mastoid segment?
Passes through this after passing between the stapes and the lateral semicircular canal
Exits the temporal bone via the stylomastoid foramen
Supplied by the stylomastoid artery
Shows variable branching patterns in the face
Is the course of the facial nerve vulnerable to many neoplastic, traumatic, and infectious conditions?
Yes
A lot of different parts of the nerve
What is the incidence of newborn facial paralysis?
About 0.2%
How can pediatric facial nerve paralysis develop?
Congenital
Prenatal acquired
Postnatal acquired
What is the cause of congenital pediatric facial nerve paralysis?
Development errors during embryogenesis
What is the cause of prenatal acquired pediatric facial nerve paralysis?
Intrauterine trauma (forceps compression during delivery or compression of the side of face against sacrum during labor)
Fetal exposure to teratogens (maternal rubella)
What is the time period of prenatal?
One month before and after birth
What is the cause of postnatal acquired pediatric facial nerve paralysis?
Many of the same conditions that can affect adults (trauma and infections)
Is osteopetrosis a congenital facial nerve disorder?
Yes
How is osteopetrosis inherited?
AD
Is osteopetrosis present at birth?
Yes
It has varying severity and is milder than the AR condition
Is osteopetrosis a bony dysplasia?
Yes
It causes the bones to harder and become denser
Does osteopetrosis result in multiple cranial neuropathies?
Yes
Because of bony obliteration of neural foramina with entrapment and compression of cranial nerves
Can osteopetrosis result in congenital facial paralysis and vision and hearing loss?
Yes
Due to the progressive and fluctuating involvement of CN II, V, VII, and VIII
What is the treatment for osteopetrosis?
Symptomatic
Facial nerve decompression if nerve entrapment and associated facial dysfunction
Is mobius syndrome a congenital facial nerve disorder?
Yes