GEN-ANA-LAB_Muscles-of-Mastication_Facial-Expressions

Muscles of Mastication

Muscles responsible for the movement of the jaw during chewing and speaking.

Elevation of mandible

Function of Masseter

Masseteric nerve from the anterior trunk of the mandibular nerve [V3]

Innervation of Masseter

Superficial part: angle of the mandible and related posterior part of the lateral surface of the ramus of the mandible

Deep part: central and upper part ramus of mandible as high as the coronoid process.

Insertion of Masseter

Superficial part: maxillary process of the zygomatic bone and the anterior two-thirds of the zygomatic process of the maxilla.

Deep part: medial aspect of the zygomatic arch and posterior part of its inferior margin

Origin of Masseter

Bone of temporal fossa and temporal fascia

Origin of Temporalis

Coronoid process of mandible and anterior margin of ramus of mandible almost to last molar tooth

Insertion of Temporalis

Deep temporal nerves from the anterior trunk of the mandibular nerve [V3]

Innervation of Temporalis

Elevation and retraction of mandible. Also participates in side to side movements

Function of Temporalis

Deep head: medial surface of lateral plate of pterygoid process and pyramidal process of palatine bone Superficial head: tuberosity of maxilla and pyramidal process of palatine bone

Origin of Medial Pterygoid

Medial surface of mandible near angle

Insertion of Medial Pterygoid

Nerve to medial pterygoid from the mandibular nerve [V3]

Innervation of Medial Pterygoid

Elevation and side to side movements of the mandible

Function of Medial Pterygoid

Protrusion and side-to-side movements of the mandible

Function of Lateral Pterygoid

Nerve to lateral pterygoid from the anterior trunk of mandibular nerve [V3] or form buccal branch

Innervation of Lateral Pterygoid

Capsule of temporomandibular joint in the region of attachment to the articular disc and to the pterygoid fovea on the neck of the mandible

Insertion of Lateral Pterygoid

Upper head: roof of infratemporal fossa

Lower head: lateral surface of lateral plate of the pterygoid muscle

Origin of Lateral Pterygoid

Oral Group
Nasal Group
orbital group
auricular group
scalp group (occipitofrontalis)
neck group

Divisions of Muscle of Facial Expressions

a. Orbicularis oris
b. Depressor anguli oris
c. Levator anguli oris
d. Zygomaticus major
e. Zygomaticus minor
f. Levator labii superioris
g. Levator labii superioris alaeque nasi
h. Depressor labi inferioris
i. Risorius
j. Mentalis
k. Buccinator

oral group

a. Compressor naris
b. Dilator naris
c. Depressor septi
d. Procerus

nasal group

a. Orbicularis oculi
b. Corrugator supercili

orbital group

a. Auricular anterior
b. Auricular superior
c. Auricular posterior

auricular group

a. Frontalis
b. Occipitalis

scalp group (occipitofrontalis)

a. Platysma

neck group

Contains two muscles associated with the eye socket. These muscles control the movements of the eyelids, important in protecting the cornea from damage.

orbital group

Masseter

Muscle of mastication that elevates the mandible, with origins on the zygomatic bone and insertions on the mandible.

Temporalis

Muscle of mastication that elevates and retracts the mandible, with origins on the temporal bone and insertions on the mandible.

Medial Pterygoid

Muscle of mastication that aids in elevation and side-to-side movements of the mandible.

Lateral Pterygoid

Muscle of mastication that helps in protrusion and side-to-side movements of the mandible.

Orbicularis Oris

Muscle responsible for puckering the lips, with origins on the maxilla and insertions on the skin and mucous membranes of the lips.

Buccinator

Muscle located between the mandible and maxilla, aiding in pulling the cheek inwards against the teeth.

Depressor Septi Nasi

Muscle assisting in opening the nostrils, with attachments from the maxilla to the nasal septum.

Nasalis

Muscle involved in compressing and opening the nostrils, with transverse and alar parts originating from the maxilla.

Procerus

Muscle that pulls the eyebrows downward to produce wrinkles over the nose,