Transcript TMJ and Muscles of Mastication

Temporomandibular joint
and
Muscles of Mastication
Dr. Sama ul Haque
Objectives
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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.
Mandible
Mandible (Outer aspect)
Mandible (Inner aspect)
Temporo-Mandibular Joint (TMJ)
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Mandibular fossa of temporal bone with
condyle of mandible
Two joint cavities with articular disc
interposed
Lower cavity = hinge joint
Upper joint = gliding
TMJ
TMJ
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Capsule
• Surrounds the joint
• Encloses the disc
• Attaches above the margins of the mandibular
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fossa
To the neck of the mandible
Inner aspect of capsule attaches to disc
Above disc – capsule loose
Below disc - taut
TMJ Capsule & Ligaments
TMJ Joint Cavity
TMJ
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Movements
Elevation
Depression
Retraction
Protraction
Side to side
TMJ Motions
TMJ
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Side to side – grinding movements
• Mandible is alternately protracted and
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retracted with the two sides moving in
opposite directions so that one side is
protracted while the other is retracted
Actions combined with elevation and
depression, rhythmically and alternately
Muscles of Mastication
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1. Masseter
2. Temporalis
3. Lateral pterygoid
4. Medial pterygoid
All innervated by CN V (Trigeminal)
Opening of jaw (depression) primarily
passive or gravity assist.
Masseter
Temporalis
Pterygoids
Pterygoids
Pterygoids
TMJ Motions
Maxillary Artery
Maxillary Artery
Thank you