Anatomy Week 6

Front 1

masseter

Back 1

Quadrate muscle attaching to inferior border and medial surface of maxillary process of zygomatic bone and the zygomatic arch

Angle and lateral surface of ramus of mandible

Anterior trunk of mandibular nerve (CN V3) via masseteric nerve

Elevates mandible; superficial fibers make limited contribution to protrusion of mandible

Front 2

buccinator

Back 2

Mandible, alveolar processes of maxilla and mandible, pterygomandibular raphe

Angle of mouth; orbicularis oris

Presses cheek against molar teeth; works with tongue to keep food between occlusional surfaces and out of oral vestibule; resists distension (when blowing)

Front 3

orbicularis oculi

Back 3

Medial orbital marginl medial palpebral ligament; lacrimal bone

Skin around margin of orbit; superior and inferior tarsi

Closes eyelids; palpebral part does so gently, orbital part tightly

Front 4

orbicularis oris

Back 4

Medial maxilla and mandible; deep surface of peri-oral skin; angle of mouth

Mucous membrane of lips

Tonus closes mouth; phasic contraction compresses and protrudes lips (kissing) or resists distension (blowing)

Front 5

occipitofrontalis

Back 5

Frontal belly: From epicranial aponeurosis to skin and subcutaneous tissue of eyebrows and forehead. Elevates eyebrows and wrinkles skin of forehead; protracts scalp (indicating surprise or curiosity)

Occipital belly: From lateral two-thirds of superior nuchal line to epicranial aponeurosis. Retracts scalp; increases effectiveness of frontal belly

Front 6

medial pterygoid

Back 6

Quadrangular two-headed muscles from a) medial surface of lateral pterygoid plate and pyramidal process of palatine bone and b) tuberosity of maxilla

Medial surface of ramus of mandible, inferior to mandibular foramen; in essence, a mirror image of the ipsilateral masseter, the two muscles flanking the ramus

Front 7

temporalis

Back 7

Triangular muscle with broad attachment to floor of temporal fossa and deep surface of temporalis fascia

Narrow attachment to tip and medial surface of coronoid process and anterior border of ramus of mandible

Anterior trunk of mandibular nerve (CN V3) via deep temporal nerves

Elevates mandible, closing jaws; posterior, more horizontal fibers are retractors of mandible

Front 8

lateral pterygoid

Back 8

Triangular two-headed muscle from a) infratemporal surface and crest of greater wing of sphenoid and b) lateral surface of lateral pterygoid plate

Superior head attaches primarily to joint capsule and articular disc of TMJ; inferior head attaches primarily to pterygoid fovea on anteromedial aspect of neck of condyloid process of mandible

Anterior trunk of mandibular nerve (CN V3) via nerves to lateral pterygoid

Acting bilaterally, protracts mandible and depresses chin; acting unilaterally, swings jaw toward contralateral side; alternate unilateral contraction produces larger lateral chewing movements

Front 9

zygomaticus major

Back 9

Zygomatic bone

Angle of mouth, where fibers blend with those of the levator and depressor anguli oris muscles and with the orbicularis oris

Draws the angle of the mouth upwards and backward, as in laughing

Front 10

depressor anguli oris

Back 10

Arises from the oblique line of the mandible

Inserts into the angle of the mouth

Depresses the angle of the mouth and is an antagonist of the levator anguli oris and zygomaticus major

Front 11

Which muscles close the mouth?

Back 11

temporalis, masseter, medial pterygoid

Front 12

Which muscles open the mouth?

Back 12

lateral pterygoid, suprahyoid and infrahyoid muscles (+gravity)

Front 13

Which muscles protrude the chin?

Back 13

lateral pterygoid, masseter, medial pterygoid (mostly lateral pterygoid)

Front 14

Which muscles retrude the chine?

Back 14

temporalis and masseter

Front 15

Which muscles make lateral movements?

Back 15

temporalis of same side, pterygoids of opposite side, masseter