1. TMJ & Muscles of mastication
D.Rania Gabr
D.Sama.
D.Elsherbiny

2. Objectives Identify the parts of the mandible.
Know the type and formation of temporomandibular joint.
Understand the attachment of the capsule and ligaments of the temporomandibular joint.
Explain the mechanism of movements taking place at temporomandibular joint.
Define the stability factors of the joint.
Explain the muscles of mastication with their origin, insertion, nerve supply and actions.
Discuss maxillary artery.

3. Nerve supply: Mandibular nerve (trigeminal nerve).
Action
All elevate the mandible except lateral pterygoid “depress”
All protrude the mandible except temporalis “retract”
2 muscles (medial & lateral pterygoid) produce side to side movement.

5. TEMPORAL FASCIA Attachment: Above: Superior temporal line Below:
It splits into 2 layers and insert into respective borders of zygomatic bone

6. Temporalis
Origin: Medial wall of the temporal fossa and temporal fascia Insertion: Anterior margin of coronoid process and anterior border of the ramus of mandible
Masseter
Origin:
Lower margin & deep aspect of zygomatic arch
Insertion:
Lateral surface of ramus of mandible

7. Lateral pterygoid Medial pterygoid Origin:
Upper head: Infratemporal surface of greater wing of sphenoid
Lower head: Lateral surface of the lateral pterygoid plate
Insertion: Pterygoid fovea & capsule of TMJ.
Medial pterygoid
Origin:
Deep head: from the medial surface of lateral pterygoid plate
Superficial head: Tuberosity of maxilla
Insertion: inner surface of angle of mandible.

8. TEMPOROMANDIBULAR JOINT
Type: synovial condylar.
Articular surfaces;
Above: mandibular fossa and articular tubercle.
Below: head of mandible.
Articular disc:
Divides the cavity into 2 cavities:
upper: for protrusion & retraction.
Lower; for rotation.

9. Ligaments:
lateral temporomandibular ligament.
Sphenomandibular ligament.
Stylomandibular ligament.
Arterial supply:
Maxillary artery and superficial temporal artery.
Nerve supply:
Auriculotemporal nerve and nerve to massster

10. Movement of TMJ Elevation: temporalis, masseter, medial pterygoid.
Depression: gravity, lateral pterygoid, mylohyoid, digastric, geniohyoid.
Protraction: masster , medial and lateral pterygoid.
Retraction: temporalis and digastric

11. Clinical Anatomy Trismus:
Tonic spasm of both masseters is the characteristic symptom of tetanus which produces “lock jaw”

12. Clinical Anatomy (contd...)
Paralysis of lateral pterygoid muscles causes the jaw to deviate towards the paralysed side on opening the mouth as a result of action of normal muscle.