Muscles of Mastication and Facial Expression

Medial (internal) pterygoid

Medial (internal) pterygoid insertion/origin/action

o. medial surface of the lateral pterygoid plate & pterygoid fossa

i. medial surface of the ramus and angle of mandible

a. elevate mandible (bilateral contraction)

contralateral (one side) execursion/deviation (move mandible to opposite side from the muscle).

Lateral (external) pterygoid

Lateral (external) pterygoid origin/insertion/action

o. Superior head – infratemporal crest (great wing of sphenoid bone)

Inferior head - lateral surface of lateral pterygoid plate

i. Articular disc of TMJ and neck of the mandibular condyle

a. bilaterally protrude jaw and depress mandible (open mouth)

unilaterally: contralateral excursion of mandible (move to opposite side of muscle)

Temporalis origin/insertion

o. Temporal line of the temporal fossa

i. Coronoid process and anterior border of mandibular ramus

Temporalis

Superficial part of Masseter origin/insertion

o. Zygomatic process of maxilla and anterior 2/3 of inferior border of the zygomatic arch

i. Angle and lower lateral ramus of mandible

Deep part of Masseter origin/insertion

o. Inner surface of posterior 1/3 of zygomatic arch

i. Superior part of mandibular ramus and lateral surface of coronoid process

Masseter

Accessory muscle of mastication name

Buccinator

Buccinator

Pterygomandibular space boundries

a. Lateral – medial surface of mandibular ramus

b. Medial – lateral surface of medial pterygoid

c. Superior – lateral pterygoid

d. Inferior – insertion of medial pterygoid

Pterygomandibular space contents

a. Lingual nerve

b. Inferior alveolar nerve and artery

Pterygomandibular space

Orbicular oculi

Orbicular oris

Procerus

Nasalis

Zygomaticus major

Zygomaticus minor

Levator labii superioris

Levator labii superioris alaeque nasi

Levator anguli oris

Depressor anguli oris

Depressor labii inferioris

Mentalis

Buccinator

Risorius

Frontalis

Occipitalis

Platysma

Corrugator supercilli

Cutaneous innervation of the face

trigeminal nerve (CN5)

a. Ophthalmic

b. Maxillary

c. Mandibular

Artery Supply to Face

a. Facial

b. Superficial temporal

Vein Supply to Face

facial

Ophthalmic branch v1

green

Maxillary branch v2

purple

Mandibular branch v3

red

Muscles of Facial Expression are derived from which brachial arch

2nd brachial arch

Muscles of Facial Expression are innervated by which cranial nerve

Facial nerve (VII)

Muscles of Mastication are derived from which brachial arch

1st brachial arch

Muscles of mastication are innervated by which cranial nerve

Mandibular nerve (V3, branch of trigeminal V)

Why are the Platysma and Corrugator supercilli muscles exceptions to the muscles of facial expression?

Due to their unusual locations while still using VII innervation

Temporalis o/i/a

o: temporal fossa, temporal fascia

i: apex and medial surface of coronoid process, anterior border of ramus

a: elevator of mandible

retraction of mandible

unilateral contraction leads to ipselateral (same side) contraction of mandible

superficial part of masseter o/i/a

o: zygomatic process of the maxilla

i: angle, ramus, and body of mandible

a: elevate mandible, protrude mandible, ipselateral excursion

deep part of masseter o/i/a

o: Posterior one-third of the inferior border and medial/deep surface of the zygomatic arch.

i: ramus and periosteum of ramus

a: elevate mandible, protrude mandible, ipselateral excursion

buccinator muscle o/i/a

o: alveolar processes of maxilla/mandible, Pterygomandibular Raphe

i: Modiolus (node near corner of mouth)

a: mastication and facial expression/blowing

parotid gland

orbicularis oculi action

closes eye

orbicularis oris action

closes mouth

procerus action

produces transverse wrinkling between the eyes

Nasalis action

compress/dilate nostrils

Zygomaticus major/minor action

smiling by raising the angle of the mouth

Levator labii superioris action

elevates upper lip

Levator labii superioris alaeque nasi actions

dilates nostrils, elevates upper lip

Levator anguli oris action

elevates angle of the mouth

Depressor anguli oris action

depresses angle of the mouth

Depressor labii inferioris action

depresses lower lip

mentalis action

protrudes lower lip (pout)

buccinator action

compress cheek to maintain pocket for food

Risorius action

draw back angle of oral cavity

Occipitofrontalis action

wrinkle forehead

Platysma action

tenses skin of neck, works with lateral pterygoid to depress mandible

corrugator supercilli action

draw eyebrows down/medially (as if frowning)