UNIT 5: Muscles of Facial Expression Flashcards
most muscles of facial expression act on the
mouth
muscles of facial expression act _____ to create facial expressions
together
muscles of facial expression are unique bc
no discrete fascial sheath encasing the muscle
insert directly into the skin (w/o a tendon)
1 muscle of the scalp w two bellies
epicranius
frontalis and occipitalis bellies
frontalis belly of epicranius: O, I, A, Inn
O = epicranial aponeurosis
I = skin of eyebrows and root of nose
A= raises eyebrows w aponeurosis fixed, wrinkles forehead
I = CN VII, temporal branch
Occipitalis belly of epicranius: O, I, A, Inn
O = occipital and temporal bones
I = epicranial aponeurosis
A = fixes apponeurosis, pulls scalp posteriorly
Inn = CN VII, posterior auricular branch
two muscles of the eyes
orbicularis oclui and corrugator supercilli
orbicularis oculi: O, I, A, Inn
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
Corrugator supercilli: O, I, A, Inn
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
4 muscles of the nose
procerus
depressor septi nasi
nasalis, compressor naris
nasalis, dilator naris
procerus: O, I, A, Inn
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
depressor septi nasi: O, I, A, Inn
O = maxillary incisive fossa
I = nasal septum and alar cartilage
A = contricts nostrils
Inn = CN, VII, zygomatic and buccal branches
nasalis, compressor naris: O, I, A, Inn
O = maxilla
I = bridge of nose
A= compresses back of the nose
Inn = CN VII, Zygomatic and buccal branches
nasalis, dilator naris: O, I, A, Inn
O = nasal notch of maxilla
I = alar cartilage
A = dilates nostrils
Inn = CN VII, zygomatic and buccal branches
what is the orbicularis oris - how is it intrinsic and extrinsic?
muscle of the mouth
deep unpaired oval ring of muscle fibres (intrinsic)
superficial fibres from other muscles that insert into lips (extrinsic)
orbicularis oris: O, I, A, Inn
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
what are the three categories of extrinsic muscles that converge on the lip
transverse
angular
vertical
transverse extrinsic muscles
course horizontally from origin to insert into the corner of the mouth and orbicularis oris
angular extrinsic muscles
approach corners of mouth obliquely from above and below
vertical extrinsic muscles
enter lip directly from above and below
modiolus
central axis located at the corners of the mouth
region where fibres from extrinsic lip muscles converge to intermingle w intrinsic orbicularis fibres
damage to modiolus has….
major effect bc it interferes w cross over of muscle fibres
levator labii superioris alaeque nasi: O, I, A, Inn
O = frontal process of maxilla
I = alar cartilage and upper lip
A= elevates upper lip; flares nostril
Inn = zygomatic and buccal branches of VII
levator labii superioris: O, I, A, Inn
O = infraoribital margin
I = upper lip lateral to alaeque nasi
A = elevates and everts upper lip
Inn = zygomatic and buccal branches of VII
Levator anguli oris: O, I ,A, Inn
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
zygomaticus minor (medial): O, I, A, Inn
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
zygomaticus major (lateral): O, I, A, Inn
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
Risorius: O, I, A, Inn
O = fascia of masseter
I = modiolus
A = retracts corner of mouth, pulls lips toward teeth
Inn = zygomatic and buccal branches of VII
deepest facial muscle
buccinator