Temporomandibular Joint and muscles of Mastication

Which of the muscles of mastication does not elevate/close the jaw? A. Masseter m. B. Temporalis m. C. Lateral Pterygoid m. D. Medial Pterygoid m.

Lateral Pterygoid m.

Which is the only muscle of mastication that opens the jaw? What other action does it do as well?

Lateral Pterygoid m. Depresses/opens mandible and protrudes mandible

Temporal Fossa Location Content

Lateral Skull above zygomatic arch Contents: Temporalis Muscle also: branches of facial artery and Maxillary nerve (V2)

Masseter m. Origin- Insertion Innervation Action

Origin: Zygomatic Arch and bone Insertion: Angle of mandible and lateral surface of ramus Innervation: mandibular division of trigeminal n. Action: Elevates Mandible

Articulating surfaces of Temporomandibular joint Temporal bone Mandible

Temporal Bone -Mandibular Fossa -Articular Tubercle Disc in between Mandible: Mandibular Condyle

Medial Pterygoid m. Action

elevates and protracts the mandible

Masseter m. Action

elevates the mandible

Temporalis m. Action

elevates the mandible; retracts the mandible (posterior fibers)

Infratemporal Fossa

• Location = lateral skull inferior to temporal fossa and deep to zygomatic arch Contents = • Temporalis Muscle • Pterygoid Muscles • Middle Meningeal Artery • Branches of the mandibular nerve • Branch of facial nerve • Branch of glossopharyngeal nerve • Otic Ganglion • Also: pterygomaxillary fissure

Depress jaw means to _____ the jaw

open the jaw

Lateral Pterygoid m Action

opens the mouth; active in grinding actions of chewing protracts the mandible;

When jaw opens the mandibular condyle and disc glides _______ on tubercle and slide ______ when you close your mouth

When jaw opens the mandibular condyle and disc glides FORWARD and DOWN on tubercle and slide back when you close your mouth

Ptyergopalantine fossa Content

-Pterygopalatine ganglion (parasymapthetic, lacrimal, related to cranial nerve VII) - Maxillary nerve - Branches of facial nerve - Facial artery branch

Pterygopalatine Fossa Content

Foramen rontunda with maxillary nerve inferior orbital fissure Pterygopalantineganglion

This is an x-ray of what?

Fracture of anterior body of mandible

This is an x-ray of? Answer

Fracture of the head of mandible

Medial Pterygoid plate originates where?

MEDIAL surface of LATERAL pterygoid plate

Temporomandibular Joint allows for what movement in the mandible Main Others Type of movement

Main: -Depression (open) and elevation of mandible (close) (i.e opening and closing the mouth) Other: -Retraction/Protrusion - Lateral Deviation (condlye of mandible- mandibular fossa with disc in btwn) Type of movement: Gliding and rotation movement at the joint itself not in mouth

Muscles of Mastication are innervated by what nerve

Mandibular nerve CNV3

Which muscle is pure closer of the jaw

Masseter M.

Muscles of Mastication List

Masseter m. Temporalis m. Lateral Pterygoid m. Medial Pterygoid m.

Which muscle elevates/closes the jaw?

Masseter m. Temporalis m. Medial Pterygoid m.

Artery under Pterion is ?

Middle menigeal artery

Lateral Pterygoid m. Origin Insertion Innervation Action

Origin: insertion: lateral aspect of lateral pterygoid plate AND Greater wing of the Sphenoid Insertion: Capsule and disk of TMJ Innervation: mandibular branch of CNV Action: Depresses/opens mandible and protracts

Lateral Pterygoid m. Origin- Insertion Innervation Action

Origin: greater wing of the sphenoid bone; and lateral surface of the lateral pterygoid plate Insertion: capsule and disk of TMJ Innervation: Mandibular branch of Trigeminal nerve Action: Deppresses/ opens the mouth; protracts the mandible; active in grinding actions of chewing

Medial Pterygoid m. Origin- Insertion Innervation Action

Origin: medial surface of lateral pterygoid plate Insertion: angle and medial surface of ramus of mandible Innervation: mandibular branch of Trigeminal Action: Elevates/closes mandible

Temporalis m. Origin- Insertion Innervation Action

Origin:Temporal Fossa Insertion: coronoid process of mandible Innervation: Mandibular Nerve CNV3 Action: elevates mandible and retracts mandible

Elevate the jaw means to _____ the jaw

close the jaw

If the ______ muscle was not working well on only one side it will move it from side to side.

lateral pterygoid m.