Download 05 – TMJ Muscles

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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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