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TMJ Muscles. 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
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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.
Temporalis O: Temporal fossa I: Coronoid process/Ramus of mandible A: Elevation of Mandible N: CN V (Trigeminal nerve) Palpation: page 83
Masseter 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
Lateral Pterygoid O: Sphenoid bone I: Mandible & TMJ A: Protraction of Mandible N: CN V (Trigeminal nerve) Palpation: page 89
Medial Pterygoid O: Sphenoid bone I: Internal surface of Mandible A: Elevates and protracts the mandible N: CN V (Trigeminal nerve) Palpation: page 92