UNIT 5: Muscles of Facial Expression Flashcards

1
Q

most muscles of facial expression act on the

A

mouth

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2
Q

muscles of facial expression act _____ to create facial expressions

A

together

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3
Q

muscles of facial expression are unique bc

A

no discrete fascial sheath encasing the muscle

insert directly into the skin (w/o a tendon)

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4
Q

1 muscle of the scalp w two bellies

A

epicranius

frontalis and occipitalis bellies

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5
Q

frontalis belly of epicranius: O, I, A, Inn

A

O = epicranial aponeurosis
I = skin of eyebrows and root of nose
A= raises eyebrows w aponeurosis fixed, wrinkles forehead
I = CN VII, temporal branch

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6
Q

Occipitalis belly of epicranius: O, I, A, Inn

A

O = occipital and temporal bones
I = epicranial aponeurosis
A = fixes apponeurosis, pulls scalp posteriorly
Inn = CN VII, posterior auricular branch

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7
Q

two muscles of the eyes

A

orbicularis oclui and corrugator supercilli

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8
Q

orbicularis oculi: O, I, A, Inn

A

O = frontal and maxillary bones
I = lateral palpebral raphe
A= closes eye, tight closure can also draw eyebrows downward
Inn = CN VII, temporal and zygomatic branches

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9
Q

Corrugator supercilli: O, I, A, Inn

A

O = arch of frontal bone above nasal bones
I = skin of eyebrow
A = draws eyebrows together and wrinkles forehead vertically
Inn = CN VII, Temporal branch

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10
Q

4 muscles of the nose

A

procerus
depressor septi nasi
nasalis, compressor naris
nasalis, dilator naris

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11
Q

procerus: O, I, A, Inn

A

O = nasal bone and lateral nasal cartilage
I = skin over the glabella (bw eye brows)
A = wrinkles nose
Inn = CN VII, temporal and zygomatic branches

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12
Q

depressor septi nasi: O, I, A, Inn

A

O = maxillary incisive fossa
I = nasal septum and alar cartilage
A = contricts nostrils
Inn = CN, VII, zygomatic and buccal branches

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13
Q

nasalis, compressor naris: O, I, A, Inn

A

O = maxilla
I = bridge of nose
A= compresses back of the nose
Inn = CN VII, Zygomatic and buccal branches

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14
Q

nasalis, dilator naris: O, I, A, Inn

A

O = nasal notch of maxilla
I = alar cartilage
A = dilates nostrils
Inn = CN VII, zygomatic and buccal branches

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15
Q

what is the orbicularis oris - how is it intrinsic and extrinsic?

A

muscle of the mouth

deep unpaired oval ring of muscle fibres (intrinsic)

superficial fibres from other muscles that insert into lips (extrinsic)

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16
Q

orbicularis oris: O, I, A, Inn

A

O = facial midline (maxilla and mandible)
I = inserts into muscles and ski at angles of the mouth (modiolus)
A= closes and protrudes lips; compresses lips for bilabial sounds
Inn = buccal and mandibular branches of VII

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17
Q

what are the three categories of extrinsic muscles that converge on the lip

A

transverse
angular
vertical

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18
Q

transverse extrinsic muscles

A

course horizontally from origin to insert into the corner of the mouth and orbicularis oris

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19
Q

angular extrinsic muscles

A

approach corners of mouth obliquely from above and below

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20
Q

vertical extrinsic muscles

A

enter lip directly from above and below

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21
Q

modiolus

A

central axis located at the corners of the mouth

region where fibres from extrinsic lip muscles converge to intermingle w intrinsic orbicularis fibres

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22
Q

damage to modiolus has….

A

major effect bc it interferes w cross over of muscle fibres

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23
Q

levator labii superioris alaeque nasi: O, I, A, Inn

A

O = frontal process of maxilla
I = alar cartilage and upper lip
A= elevates upper lip; flares nostril
Inn = zygomatic and buccal branches of VII

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24
Q

levator labii superioris: O, I, A, Inn

A

O = infraoribital margin
I = upper lip lateral to alaeque nasi
A = elevates and everts upper lip
Inn = zygomatic and buccal branches of VII

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25
Q

Levator anguli oris: O, I ,A, Inn

A

O = canine fossa below infraorbital margin
I = fibres converge to modiolus
A= pulls corners of lips superiorly; deepens nasolabial fold (smiling/laughing)
Inn = zygomatic and buccal branches of VII

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26
Q

zygomaticus minor (medial): O, I, A, Inn

A

O= zygomatico-maxillary suture
I = converge to modiolus (run inferiorly and medially)
A = elevates upper lip and deepens nasolabial fold
Inn = zygomatic and buccal branches of VII

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27
Q

zygomaticus major (lateral): O, I, A, Inn

A

O = body of zygomatic bone
I = converge to modiolus
A = pulls lateral corners of the mouth superiorly and laterally (smiling/laughing)
Inn = zygomatic and buccal branches of VII

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28
Q

Risorius: O, I, A, Inn

A

O = fascia of masseter
I = modiolus
A = retracts corner of mouth, pulls lips toward teeth
Inn = zygomatic and buccal branches of VII

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29
Q

deepest facial muscle

A

buccinator

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30
Q

buccinator: O, I, A, Inn

A

O = maxilla, alveolar margin; mandible, oblique line; pterygomandibular raphe (meets superior constrictor muscle)
I = modiolus
A = compresses lips and draws them toward teeth; compresses the cheeks; relaxed - cheeks puff up “bugler’s muscle”
Inn: buccal branch of VII

31
Q

depressor anglui oris: O, I, A, Inn

A

O = oblique line of mandible
I = fibres pass thru modiolus to deeper layers
A = draws corners of mouth downward and laterally
Inn = mandibular and buccal branches of VII

32
Q

depresor labii inferioris: O, I, A, Inn

A

O = arises deep to DAO along oblique line
I = lower lip
A = depresses lower lip as in pouting
Inn = mandibular and buccal branches of VII

33
Q

mentalis: O, I, A, Inn

A

O = mental symphysis of mandible
I = passes thru DLI to insert in skin inferior to orbicularis oris
A = protrudes and everts lower lip and wrinkles chin
Inn = mandibular branch of VII

34
Q

Platysma is …

A

a neck muscle, very thin, superficial, wide and flat

aka shaving muscle

35
Q

platysma: O, I, A, Inn

A

O = fascia overlying petoralis major and deltoid
I = corner of mouth (modiolus), cheeks and muscles of mouth
A = lowers jaw, pulls lower lip down and back, tenses skin of neck
Inn = cervical branch of VII

36
Q

what 4 fibre types does the facial nerve have?

A

special visceral efferent
general visceral efferent
special visceral afferent
general somatic afferent

37
Q

SVE of CN VII innervate…

A

muscles of facial expression (and auricular muscles around the ear), plus stapedius, stylohyoid, and the posterior belly of digastric

all of these muscles are derived from the 2nd branchial arch

38
Q

GVE of CN VII innervate…

A

the lacrimal gland, submandibular and sublingual salivary glands, mucous membranes of nose and hard and soft palate

39
Q

SVA of CN VII are for

A

taste sensation from the anterior 2/3 of the tongue

40
Q

GSA of CN VII are for

A

sensations from skin of concha of the external ear, skin behind ear, external auditory meastus, external tympanic membrane

41
Q

in CN VII, ____ fibres which are majority of the nerve are separated from the rest of the nerve…. remaining fibres, ____, ____, ____ are bound in a fascial sheath and called _____ ______

A

SVE
GVE, SVA, GSA
Nervus intermedius

42
Q

describe the course of the facial nerve (generally)

A

all CN VII fibres emerge at lower border of pons

enter the petrous temporal bone via internal acoustic meatus

fibres travel thru petrous bone, there is a swelling of the nervus intermedius: geniculate ganglion

other fibres continue in facial canal

SVE and GSA fibres leave skull thru stylomastoid foramen

43
Q

in the course of the facial nerve there is a swelling in the petrous bone that fibers pass thru, it is called the

A

geniculate ganglion

44
Q

in the course of the facial nerve, the geniculate ganglion is where …

A

the greater petrosal nerve branches off - which are GVE fibres to glands in the upper head

45
Q

in the course of the facial nerve, some fibres continue in facial canal, one branch of SVE fibres leaves to…

A

innervate the stapedius m in the middle ear

46
Q

in the course of the facial nerve, some fibres continue in facial canal: _____ _____ (SVA fibres) branches from nervus intermedius and passes through the middle ear cavity and exits thru the ____ ______, which travels to….

A

chorda tympani
petrotympanic fissure
travels to the tongue, oral cavity to support taste and salivary secretion

47
Q

SVE of CN VII have 3 major functions

A

facial expressions
acoustic reflex (stapedius)
elevating an retracting hyoid bone (stylohyoid and posterior belly of digastric)

48
Q

lower motor neuron of CN VII SVE has cell bodies in _______ in the _____

A

facila motor nucleus
pons

49
Q

the facial motor nucleus for CN VII SVE, receives _____ info from the cortex for facial muscles above the eye, and receives _____ info only for muscles below the eye

A

bilateral (contralateral and ipsilateral)
contralateral

50
Q

describe the intracranial pathway for CN VII SVE

A

the fibres bend around abducens nucleus

axons leave the caudal border of the pons –> enter internal acoustic meatus w nerve intermedius and CN VII

passes by geniculate ganglion –> travels w/i facial canal of petrous bone

branches to stapedius muscle –> remaining fibres emerge thru stylomastoid foramen

51
Q

describe the extra-cranial pathway of CN VII SVE

A

after passing thru stylomastoid foramen –> posterior auricular nerve (to occuputalis m and auricular m) and muscular branch (nerve to posterior belly of digastric, nerve to stylohyoid m)

remaining SVE fibres travel thru the parotid salivary gland (from surface to deep) = parotid plexus …. divides into 5 branches that innervate muscles of facial expression

52
Q

what are the 5 branches of the parotid plexus of CN VII SVE?

A

temporal nerve
zygomatic nerve
buccal nerve
mandibular nerve
cervical nerve

53
Q

tumour in the _____, _____, or ______ will usually result in CN VI and CN VII abnormalities such as

A

4th ventricl, pons, cerebellopontine angle

stabismus (inward eye turn), loss of facial expression bw the eye on the same side

54
Q

CN VII and CN VIII abnormalities suggest pathology in _____, bc…

A

internal auditory meatus

they travel together in the temporal bone

55
Q

muscles of the upper face receive _____ innervation, muscles of the lower face only receive ______ innervation

A

bilateral, contralateral

56
Q

upper motor neuron lesion affects muscles of facial expression ____ to eye muscles contralateral to lesion

A

inferior

57
Q

lower motor neuron lesion affects _____ muscles of facial expression ipsilateral to the lesion

A

all

58
Q

UMN lesion ex. is…. what would you see?

A

stroke in one hemisphere

drooping of lower face but able to raise eyebrows

59
Q

LMN lesion ex….. what would you see?

A

bells palsy

drooping of whole face

60
Q

CN VII GVE provides… it does not innervate the ______ gland…. its major functions are…..

A

parasympathetic innervation of glands (secretomotor) in the head

parotid gland

major functions:
crying/tearing
runny nose
salivary flow (at rest)

61
Q

describe the intracranial course of CN VII GVE

A

cell bodies in superior salivatory nucleus in the pons

receives input from hypothalamus + CNs

fibres exit pons to nervus intermedius portion of CN VII

at geniculate ganglion, divides into 2 fibres: greater petrosal nerve + chorda tympani

62
Q

describe the extra-cranial course of CN VII GVE

A

greater petrosal nerve - exits skull via foramen lacerum - supplies lacrimal/nasal glands, hard/soft palate

chorda tympani - travels thru middle ear space, exits skull via petrotympanic fissure; joins lingual notch to get to floor of mouth - supplies submandibular and sublingual salivary glands

63
Q

CN VII SVA provides…

A

taste sensation from anterior 2/3 of tongue and palate

64
Q

extra-cranial course of CN VII SVA

A

chorda tympani - travels w lingual nerve of V3… also contains visceral motor fibres for submandibular and sublingual salivary glands

65
Q

intra-cranial course of CN VII SVA

A

enter cranium thru the petrotympanic fissure –> cell bodies for taste lie in geniculate ganglion

first order sensory neurons synapse w/i rostral part of nucleus tractus solitarius, called the gustatory nucleus

fibres project to thalamus bilaterally, then to inferior part of postcentral gyrus bilaterally, the gustatory cortex (in insula)

66
Q

CN VII GSA provide…

A

sensations from skin of the concha of outer ear, skin behind the ear, external auditory meatus, external tympanic membrane

67
Q

extra-cranial course CN VII GSA

A

primary neuron enters cranium thru stylomastoid foramen, joins nervus intermedius

68
Q

intra-cranial course CN VII of GSA

A

cell bodies are contained in geniculate ganglion in temporal bone

primary neurons synapse on cell bodies of secondary neuron in nucleus of the spinal tract of CN V –> project to contralateral thalamus –> sensory cortex (post central gyrus)

69
Q

Bell’s Palsy

A

form of facial paralysis resulting from damage to/inflamation of CN VII (peripheral nerve)

70
Q

Bell’s palsy is more common …

A

pregnant females, and persons w diabetes, upper respiratory infection

71
Q

what are the signs of bell’s palsy

A

hemi facial paralysis - corner of the mouth sags, drooling, lower eyelid droops (SVE)

dependent on location of nerve damage - eye constantly drips tears (GVE), hypersensitivity to sound in the affected ear (SVE), taste impairment (SVA)

72
Q

what is the likely cause of bells palsy

A

herpes simplex virus (HSV), trauma

73
Q

bells palsy usually clears up ______ and often improves within _____ weeks, recovery almost always ________

A

untreated
2-6
complete

74
Q

how do you clinically test CN VII facial musculature

A

symmetry at rest

symmetry w motion, alternating motion (smiling, lip rounding, pouting, blinking, raising eyebrows); UMN vs LMN

range of motion and strength (lips, eyes)