Muscles of Facial Expression

Question 1

facial nerve supplies

Answer 1

general - parasympathetic to lacrimal gland, nasal and oral cavities, submandibular and sublingual gland
special sensory - taste to anterior 2/3 tongue
motor - muscles of facial expression, stylohoid and posterior digastric

Question 2

facial nerve course

Answer 2

exits via internal acoustic meatus with CN VIII
[risk of compression here]

emerges from stylomastoid foramen
2 branches -> posterior auricular and digastric nerve [pdigastric and stylohyoid]

main nerve then enters parotid with 5 branches

Question 3

5 branches of facial vein

Answer 3

temporal - occipitofrontalis, orbicularis occuli
zygomatic - orbicularis occuli, upper lip
buccal - buccinator, lip muscles
marginal mandibular - lower lip muscles
cervical - platysma

Question 4

orbicularis occuli

Answer 4

location = around eyelids
actions = close eyelids gently, softly
innervation = temporal and zygomatic of CN VII

Question 5

orbicularis oris

Answer 5

location = around mouth, buccinator and inserts into mucous membrane of lips
actions = close/protrude lips, keeps food on occlusal surfaces of teeth, pout, whistle
innervation = buccal and marginal mandibular of CN VII

Question 6

buccinator

Answer 6

location = pterygomandibular raphe to merge with orbicularis oris, pierced by parotid duct
action = keep food on occlusal surface of teeth, assists in smiling, cheeks pressed against teeth
innervation = buccal of CN VII

Question 7

platysma

Answer 7

location = base of mandible to merge with OO, skin of cheek, lower lip and mouth angle
action = tense skin of anterior face/neck, depress mandible
innervation = cervical of CN VII

Question 8

occipitofrontalis

Answer 8

location = frontal belly of epicranial apoeneurosis, tissue of eyebrows/forehead
action = retract scalp, wrinkle forehead and elevate eyebrows
innervation = temporal branch and posterior auricular branch of CN VII

Question 9

zygomaticus major and minor

Answer 9

found above the lips
major is closer to the ears
pulls angle of mouth supralaterally, laughing muscle

Question 10

depressor anguli oris

Answer 10

found under lips, angle of corner of lips
depresses corner of mouth

Question 11

zygomaticus minor

Answer 11

above lips, closer to ear
elevates upper lips exposing maxillary teeth,

Question 12

depressor labii inferioris

Answer 12

lower lip
pulls lower lip down and to the side

Question 13

levator labii superioris

Answer 13

upper lip
elevation of upper lip

Question 14

structures found in parotid gland

Answer 14

retromandibular vein
ECA - posterior auricular, maxillary, superificial temporary
CN VII [doesnt innervate]
parotid lymph nodes

Question 15

innervation of parotid gland

Answer 15

secretomotor -
* preganglionic fibres from CN IX travel otic ganglion in tympanic nerve and lesser petrosal nerve
* pass to auriculotemporal nerve CNV3 to parotid

sympathetic innervation from superior cervical ganglion , vasoconstriction and reduction fo volume in saliva

fascia/skin - great auricular nerve

Question 16

parotid duct

Answer 16

passes anteriorly to gland, over masseter, pierces buccinator and enters oral cavity near superior 2nd molars

Question 17

secretions from parotid gland

Answer 17

seromucous saliva

Question 18

anatomical relationship of parotid gland and facial nerve

Answer 18

if tumour, resection or removal needed
any damage to CN VII will cause paralysis of facial muscles
muscles will lose tone and face will sag

Question 19

describe secretomotor function innervation to parotid gland via glossopharyngeal nerve CN IX

Answer 19

CN IX provides parasympathetic innervation to produce saliva
preganglionic fibres travel to otic ganglion in tympanic nerve and lesser petrosal nerve
post ganglionic fibres pass to auriculotemporal nerve, branches to parotid gland