Lecture 1- Muscles of facial expression

Question 1

muscles of the head and face can be divided into 2 broad groups based

Answer 1

commonalities in their function and nerve supply

Question 2

2 muscle groups

Answer 2

muscles of fascial expression and muscles of mastication

Question 3

most of the muscles of facial expression lie in the

Answer 3

subcutaneosu tissues, and attach to bone, fascia and often each other

Question 4

the muscles of facial expression will act either as

Answer 4

sphincters or dilators around the orifices of the face- orbits of the eye, the nose, or mouth

Question 5

branches of the …… nerve innervate all the muscles of facial expression

Answer 5

facial

Question 6

facial nerve also knwon as

Answer 6

cranial nerve VII

Question 7

pathway of the cranial nerve

Answer 7

The facial nerve (also known as cranial nerve VII) has a complicated route from its origin at the brainstem (inside the skull) before it exits the base of the skull to become extracranial (i.e. outside skull): its origin and intracranial route will be considered in detail during a later Session. Once the facial nerve exits the skull, it runs through the substance of the parotid gland (a salivary gland that sits just anterior and inferiorly to your ear). The nerve and its branches run relatively superficial within the gland, and are vulnerable to damage in facial injuries and in disease or surgery of the parotid gland. Within the gland the facial nerve divides into five key terminal extracranial branches.

Question 8

branches of the facial nerve acronynm

Answer 8

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Question 9

list from superior to inferior the branches of the facial nerve

Answer 9

Temporal branch

Zygomatic branch

Buccal branch

Marginal mandibular branch

Cervical branch

Question 10

temporal branch innervates

Answer 10

frontalis, orblicularis, oculi, corrugator supercilli

Question 11

zygomatic branch innervates

Answer 11

orbicularis oculi

Question 12

buccal branches innervates

Answer 12

orbicularis oris, buccinator and zygomaticus

Question 13

marginal mandibular innervates

Answer 13

mentalis

Question 14

cervical branch innervates

Answer 14

platysma

Question 15

what are the muscles of facial expression

Answer 15

• orbicularis oculi
• corrugator supercilii
• orbicularis oris
• buccinator

Question 17

orbicularis oculi

Answer 17

muscle surrounds the eye socket and extends into the eyelid.

• temporal and zygomatic branches
• 3 parts
  
  • palpebral part- closes the eyelids gently
  • lacrimal part- drainage of tears
  • orbital part- tighly closes the eyelids

Question 18

Corrugator supercilii

Answer 18

is a much smaller muscle and is located posteriorly to the orbicularis oculi.

• facial nerve
• Acts to draw the eyebrows together, creating vertical wrinkles on the bridge of the nose.

Question 19

paralysis of the orbital muscles

Answer 19

If the facial nerve becomes damaged, the orbital muscles will cease to function. As they are the only muscles that can close the eyelids, this has some serious clinical consequences.

The eye cannot shut – this can cause the cornea to dry out. This is known as exposure keratitis.

The lower eyelid droops, called ectropion. Lacrimal fluid pools in the lower eyelid and cannot be spread across the surface of the eye. This can result in a failure to remove debris, and ulceration of the corneal surface.

The test for facial nerve palsy involves raising the eyebrows and closing the eyelids

Question 20

oral group of muscles

Answer 20

These are the most important group of the facial expressors: responsible for movements of the mouth and lips. Such movements are required in singing and whistling and add emphasis to vocal communication.

• orbicularis oris, buccinators etc

Question 21

orbicularis oris

Answer 21

encloses the oral cavity

• action: purses the lips

facial nevre

Question 22

buccinator

Answer 22

located between the mandible and maxilla, deep to the other muscles of the face.

• action- pulls the cheek inwards against the teeth, preventing accumulation of food in that area.
• facial nerve

Question 23

most common non-traumatic cause of facial paralysis is

Answer 23

inflammation of the facial nerve (Bell’s palsy). Inflammation of the nerve, likely viral in aetiology, causes oedema and compression of the nerve as it runs through the bones of the skull

Question 24

Weakness of the facial muscles on one side in association with an ipsilateral parotid enlargement is highly likely to be

Answer 24

a parotid cancer.

The cancerous cells invade and damage the facial nerve during its course through the gland. It is rare for benign, infective or inflammatory conditions of the parotid gland e.g. as can occur in mumps, to cause damage to the facial nerve and thus these

conditions are not typically associated with facial muscle weakness.