Facial Muscles Flashcards
Where are the facial muscles located?
subcutaneous fat/tissue beneath the skin
What cranial nerve are the facial muscles innervated by?
Cranial Nerve 7 (facial nerve)
What actions are the facial muscles responsible for?
Actions of facial expression
How do you check cranial nerve 7 with a neuro exam?
A clinician will ask a patient to perform certain facial expressions (wrinkle forehead, raise eyebrows, close eyes, smile, frown, puff out cheeks, etc.)
-looking to make sure patient is capable of making facial expressions and that they are symmetrical on both sides (to make sure both the R and L facial nerves are working)
What are the facial muscles?
-occipitofrontalis: muscle belly on the front of the forehead and on the back/base of the skull connected by CT that runs along the scalp
-orbicularis oculi
palpebral portion (gently closes lid) - runs along
eyelid
orbital portion (tightly closes lid) -wraps around the eye
-nasalis: wraps around the nose
-orbicularis oris: wraps around the mouth
-buccinator: “cheek muscle” (puff out cheeks, etc.)
-mentalis: mandible, responsible for pulling lower lip down and out
What is the pathway of cranial nerve 7 to supply the facial muscles?
-Exits the brain through the stylomastoid foramen and divides into 5 branches while passing through the parotid gland in order to innervate all facial muscles and platysma
*motor innervation
What is Bell’s Palsy and what causes it?
-Paralysis of facial muscles (seen as drooping eye, loss of nasolabial fold, drooping corner of the mouth)
-caused by an impairment of cranial nerve 7, etiology unknown but perhaps an irritation of the cranial nerve as it passes in the skull
- can be short lasting or transient yet effects can linger after the episode
-usually unilateral (99% of the time)
What is the sensory innervation of the face?
-Three branches of cranial nerve 5 (exits at foramen ovale): V1, V2, V3
V1: orbital and frontal region (exits at supraorbital foramen)
V2: maxillary region (exits at infraorbital foramen)
V3: mandibular region (exits at mental foramen)
How can you test the integrity of cranial nerve 5 for sensation in V1,V2, and V3 clinically?
Ask patient to close their eyes,
Take a fingertip or piece of cotton and gently touch the right and left sides for each area (V1-forehead, V2-cheeks, V3-jaw)
Ask patient if they can feel the touch on both sides of these areas
How would you tell which branch of cranial nerve 5 is affected by the herpes zoster virus?
The dormant Chickenpox virus will be triggered later in life and cause inflammation and rash of the skin
If in the area of the forehead/upper orbit: most likely affected in CN5 V1
If in the area of the cheek: most likely CN5 V2
If in the area of jaw/chin: most likely CN5 V3
***herpes zoster can also affect other spinal roots in the face, trunk, or lower extremities
What is trigeminal neuralgia and how is it caused?
Extremely severe facial pain that occurs along one of the root pathways of cranial nerve 5
-can be V1, V2 (most common), or V3
-caused by an abnormal irritation of cranial nerve 5 (blood vessels from the brain put pressure on CN5 resulting in trigeminal neuralgia)
