Muscles of Mastication and Facial Expression Flashcards
What muscles move the mandible
Temporalis, Masseter, lateral pterygoid, and medial pterygoid
What muscles elevate and and retract the mandible
Elevate= masseter and the temporalis
Retracts= temporalis
How does the lateral pterygoid position the mandible
Say lateral
It opens (depresses) the mandible, this is the only muscle of mastication that does this
How does the medial pterygoid position the mandible
Say medial
It closes (elevates) the mandible
Together what does the pterygoids do
move the jaw in a side to side motion to grind food
What nerve innervates all the muscles of mastication
Mandibular (V3) of the trigeminal nerve (CN3)
Where do the muscles of facial expression originate
the skull
What cranial nerve innervates all the the muscles of facial expression
CN 7 (facial)
What are the 5 Branches of the cranial nerve 7 (facial)
The= Temporal Zoo= Zygomatic Bought=Buccal More = Mandibular Camels= Cervical
Describe the occipitofrontalis muscle in terms of origin, insertion, action and innervation
Origin
- Occipital belly at the occipital lobe
- Frontal belly at the galea aponeurotica
Insertion
- Occipital belly galea aponeurotica
- Frontal belly fascia and skin above the eyes and nose
Action: raises eyebrows and wrinkles forehead skin
Innervated: temporal branch of CN 7
Describe the zygomaticus major and minor muscles in terms of origin, insertion, action and innervation
Origin: both at the zygomatic bone
Insertion:
- Major= skin and muscle at the edge of the mouth
- Minor= upper lip
Action:
- Major=draw angle of the mouth up as in smiling
- Minor=raise upper lip exposing maxillary teeth
Innervation: zygomatic and buccal branch of CN7
Describe the levator labii muscle in terms of origin, insertion, action and innervation
Origin: N/A
Insertion: skin at angle of the mouth and orbicularis oris (muscle around the lip)
Action: raises upper lip
innervation: zygomatic branch of CN7
Describe the depressor labii muscle in terms of origin, insertion, action and innervation
origin: N/a
insertion: skin of lower lip
action: lowers the lower lip
innervation: mandibular branch of CN7
Describe the depressor anguli oris muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: angle of the mouth
action: frowning, brings angle of the mouth laterally and inferiorly
innervation: mandibular branch of CN7
Describe the orbicularis oris muscle in terms of origin, insertion, action and innervation
origin: muscle fibers encircling the opening of the mouth
insertion: skin at the corner of the mouth
action: shapes lips during speech, closes protrudes lips(duck face), compresses lips against teeth
innervation: buccal branch of CN 7
Describe the risorius muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: skin at the angle of the mouth
action: grimacing look, draws angle of the mouth laterally
innervation: buccal branch of CN 7
Describe the buccinator muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: orbicularis oris
action: assists in chewing by keeping food between the teeth, presses cheeks against teeth and lips , blowing motion
innervation: buccal branch of CN7
Describe the mentalis muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: skin of chin
action: pouting face, elevates and protrudes the lower lip
innervation: mandibular branch
Describe the platysma muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: mandible, angle of the mouth, skin of the lower face
action: draws outer part of the lower lip inferiorly and posteriorly as in pouting and depressing mandible
innervation: cervical branch of CN 7
Describe the orbicularis oculi muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: circular path around the orbit
action: closes and squints the eye, elevates upper eyelid, depresses lower eyelid
innervation: temporal and zygomatic branch of CN 7
True or false the levator palpebrae superioris (opens the eye) is a muscle of facial expression
False
Describe the corrugator supercilii muscle in terms of origin, insertion, action and innervation
origin: n/a
insertion: skin of eyebrow
action: draws eyebrows inferiorly and medially, wrinkles forehead
innervation: temporal branch of CN 7
What 2 facial muscles of facial expression are innervated by 2 branches of the CN7
orbicularis oculi
zygomaticus major and zygomaticus minor
