2. Stable: Opening / Closing Muscles |
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Opening/closing motion focusing on the opening/closing muscles |
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Purposes |
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Normal coordinated muscle function. |
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Three functions of chewing muscles:
- open.
- close or elevate the mandible.
- protrude or move the jaw forwards. |
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Importance that only closing muscles
are in tension when the bite is closed. |
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Beauty of a healthy normally functioning skull. |
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Presenting |
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Point out muscles that: |
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- Open the jaw (purple) - digastric.
- Close the jaw (light blue) - masseters
and temporalis.
- Position the jaw (darker blue) - lateral pterygoids. |
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Begin to open the jaw and point out how the only muscle that functions is the digastric as the condyle merely rotates. |
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Point out how the lower pterygoid contracts to pull the lower jaw forward as the jaw opens fully and the digastric pulls it downward to full opening |
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Start closing the jaw and point out how the masseters and temporalis work and the function of elevating or closing is to pull the lower jaw as far upward towards the upper skull as the condyle seats to it's fullest upward position. |
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Explain how the upper lateral pterygoid contracts to hold the disc forward so the condyledisc assembly can return to its original position. |
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Show by moving back and forth the swelling and contracting of the very strong elevator muscles |
