BMS271 - TMJ

Question 1

Temporomandibular Joint (TMJ)

Answer 1

Modified hinge joint
- allows flexion and extension, rotation and translation
- head (of condyloid process) of mandible articulates with mandibular fossa and articular tubercle of temporal bone
- loose fibrous (joint) capsule
- joint cavity separated into two compartments by articular disc of TMJ
Ligaments
- lateral ligament of TMJ
   - thickening of TMJ capsule
   - prevents posterior dislocation
- stylomandibular ligament
- thickening of capsule of parotid gland
- sphenomandibular ligament
   - primary passive support of TMJ

Question 2

Temporalis

Answer 2

Attachments:
- temporal fossa
- coronoid process and ramus of mandible
Action:
- elevates mandible
- retracts mandible
Innervation
- mandibular nerve (CN V)

Question 3

Masseter

Answer 3

Attachments:
- zygomatic arch
- angle and ramus of mandible
Action:
- elevates mandible
Innervation
- mandibular nerve (CN V)

Question 4

Lateral Pterygoid

Answer 4

Attachments:
- lateral pterygoid plate
- TMJ capsule and disc and condyloid process of mandible
Action:
- protracts mandible
- depresses chin
- large lateral chewing movements
Innervation
- mandibular nerve (CN V)

Question 5

Medial Pterygoid

Answer 5

Attachments:
- lateral pterygoid plate
- medial surface of ramus of mandible
Action:
- elevates mandible
- protracts mandible
- small lateral chewing movements (grinding)
Innervation
- mandibular nerve (CN V)