1. TMJ Muscles

2. Muscles of Mastication (All attach onto the mandible)
Temporalis
Contributes to side-to-side grinding (lateral deviation) of mandible.
Tight temporalis may be involved with tension headaches and TMJ dysfunction
Masseter
Square-shaped muscle, divided into superficial & deep layers.
Prime mover of mandibular elevation at TMJ.
Large parotid glands are superficial to masseter.
Proportional to its size, strongest muscle in body.
Lateral Pterygoid
Aka external pterygoid.
Lateral deviation is important for grinding and chewing food.
Hypertonicity could excessively pull on TMJ structures causing dysfunction.
Medial Pterygoid
Aka internal pterygoid
Fairly thick, quadrilateral muscle
Fiber directions are identical to masseter but medial pterygoid is internal to mandible and masseter is external.

3. Temporalis O: Temporal fossa I: Coronoid process/Ramus of mandible
A: Elevation of Mandible
N: CN V (Trigeminal nerve)
Palpation: page 83

4. Masseter I: Angle, ramus`, coronoid of a mandible
O: Inferior margins of both zygomatic bone and zygomatic arch of temporal bone
I: Angle, ramus`, coronoid of a mandible
A: Elevates, protracts and retracts the mandible
N: CN V (Trigeminal Nerve)
Palpation: page 86

5. Lateral Pterygoid O: Sphenoid bone I: Mandible & TMJ
A: Protraction of Mandible
N: CN V (Trigeminal nerve)
Palpation: page 89

6. Medial Pterygoid O: Sphenoid bone I: Internal surface of Mandible
A: Elevates and protracts the mandible
N: CN V (Trigeminal nerve)
Palpation: page 92