Week 6: Face - Muscles of Facial Expression, Innervation & Vasculature, and Parotid Region

Question 1

what are the muscles of facial expression

Answer 1

buccinator
orbicularis oris
orbicularis oculi
occipitofrontalis
platysma

Question 2

what nerve (s) innervate the muscles of facial expression

Answer 2

CN VII facial

Question 3

what is the action of dilator muscles

Answer 3

act to widen the mouth or to lift or depress the corners of the mouth

Question 4

which muscles act on the nose and allow for flaring of the nostrils/ wrinkling the skin over the dorsum of the nose.

Answer 4

the alar part of nasalic acts together with the levator labii superioris alaeque nasi to flare nostrils

Procerus and the transverse part of Nasalis - wrinkle nose

Question 5

what is the main blood supply to the face

Answer 5

ECA -> Facial artery:
- labial (inferior, superior)
- lateral nasal
- angular

Question 6

branches of the ECA that supply the face

Answer 6

Facial
Maxillary
Superficial Temporal

Question 7

branches of the ICA that supply the face

Answer 7

Branches of the Opthalamic:
- Zygomaticofacial
- Zygomaticotemporal
- Supraorbital
- Supratrochlear

Question 8

what is the venous drainage of the face

Answer 8

Facial vein drains most of the face to internal jugular vein

Transverse facial vein drains some of the upper face

Question 9

what is the arterial supply to the auricular muscles

Answer 9

Branch of external carotid artery
- posterior auricular artery

Question 10

what is the venous drainage of the auricular muscles

Answer 10

external jugular vein

Question 11

what is the lymphatic drainage of the auricular muscles

Answer 11

via parotid & mastoid nodes to deep cervical nodes

Question 12

what are the layers of the eyelids

Answer 12

Skin
Connective Tissue
Conjunctiva
Muscle (orbicularis oculi)
Tarsus
Orbital septum

Question 13

what is the orbital septum

Answer 13

Anterior border of orbit continuous with periosteum

Question 14

Arterial supply of the eyelids

Answer 14

opthalamic
facial (angular)
superficial temporal

Question 15

Lymphatic drainage of eyelids is

Answer 15

via parotid nodes

Question 16

venous drainage of the eyelids

Answer 16

Medially - blood drains via the medial palpebral vein into the angular and ophthalmic veins.

Laterally - blood drains into the superficial temporal vein from the lateral palpebral vein.

Question 17

what does the parotid region cover

Answer 17

anatomically covers the area anterior to the ears and inferior to the zygomatic arch

Question 18

important structures within the parotid region

Answer 18

parotid gland and duct
facial nerve (+main divisions)
facial artery and vein

Question 19

where does the parotid gland lie

Answer 19

Lies outside of the oral cavity extending between zygomatic arch & lower border of mandible
between the SCM, external acoustic meatus & masseter

Question 20

what is the parotid gland enclosed in

Answer 20

parotid sheath

Question 21

where is the parotid duct located

Answer 21

passes horizontally from anterior edge and superficially to the masseter before piercing buccinator to enter the oral cavity near the upper 2nd molar tooth

Question 22

what is the arterial supply to the parotid gland

Answer 22

External carotid artery-> posterior auricular -> maxillary & superficial temporal (terminal branches)

Question 23

what is the venous drainage of the parotid gland

Answer 23

Retromandibular vein - from superficial temporal & maxillary

Question 24

what is the parotid plexus

Answer 24

it is the branch point of the facial nerve (extra-temporal) after it leaves the stylomastoid foramen.

Question 25

what is the parasympathetic innervation of the parotid gland

Answer 25

CN IX (glossopharyngeal)

presynaptic - from CN IX travel to the otic ganglion via the tympanic nerve & lesser petrosal nerve

postsynaptic - from the otic ganglion to parotid gland via auriculotemporal nerve (CN V3)

Question 26

what is the sympathetic innervation of the parotid gland

Answer 26

the superior cervical ganglion & the nerve plexus on the external carotid artery

Question 27

what is the infratemporal course of the facial nerve

Answer 27

• exits the pons - 2 roots (motor and sensory). 2 roots enter internal acoustic meatus –> facial canal. Roots then fuse here to form geniculate ganglion. Greater petrosal nerve branches here and supplies parasympathetic innervation to the nasal and lacrimal glands

2 more branches (within temporal)
(1) The nerve to stapedius which supplies motor to stapedius muscles of the middles ear
(2) The chorda tympani, which hitchhikes with the lingual nerve to supply taste and sensation to anterior 2/3 of the tongue

Question 28

what is the extratemporal course of the facial nerve

Answer 28

it begins when the nerve exits skull at the stylomastoid foramen

2 branches are given off
- posterior auricular - (supply the auricularis posterior + occipital belly of the occipitofrontalis muscle)
- digastric branch (supplies post. belly of digastric)

before main nerve enters the parotid gland which split into 5 branches = parotid plexus

Question 29

5 terminal (motor) branches of the facial nerve

Answer 29

temporal
zygomatic
buccal
marginal mandibular
cervical
cervical

Question 30

symptoms of Bell’s palsy

Answer 30

unilateral paralysis of upper and lower part of face

Question 31

causes of Bell’s palsy

Answer 31

unknown
theory = viral infections that could contribute to the onset of inflammation around the facial nerve

Question 32

possible treatment of Bell’s palsy

Answer 32

steroids
antivirals
Long term paralysis of the face is possible and may be treated surgically - static reconstruction

Question 33

what are the branches of the facial CNVII before the terminal branches

Answer 33

greater petrosal
chorda tympanii
posterior auricular
stapedius
nerve to digastric
nerve to stylohyoid