MUSCLE OF MASTICATION ARE AS FOLLOW;
1) MASSETER
Origin :
Superficial layer – zygomatic arch ( anterior 2/3 rd , lower border ), maxillar zygomatic process .
Deep layer – zygomatic arch deep surface .
Middle layer – zygomatic arch ( posterior 1/3 rd , lower border ).
Insertion :
Superficial layer – ramus of mandible ( lower part , lateral surface )
Deep layer – to rest of the ramus of mandible.
Middle layer – ramus of mandible ( central part ).
Action :
Elevation of mandible ( to close the mouth to bite ), protrusion ( Superficial fiber ).
Nerve supply :
Masseteric nerve ( anterior division of mandibular nerve branch ).
2) TEMPORALIS
Origin :
From Temporal fossa and temporal fascia.
Insertion :
coronoid process ( margin and deep surface ), ramus of mandible ( anterior border ).
Action :
Elevation of mandible , Side to side grinding movement , retraction of protruded mandible .
Nerve supply :
2 deep temporal branches ( from anterior division of mandibular nerve ).
3) LATERAL PTERYGOID
Origin :
Upper head – Infratemporal surface and sphenoid bone ( crest of greater wing ).
Lower fiber – lateral pterygoid plate ( lateral surface )
Insertion :
anterior surface of neck of mandible ( pterygoid fovea ).
Action :
Depression of mandible to open mouth , protudes mandible.
Nerve supply :
Branch of anterior division of mandibular nerve .
4) MEDIAL PTERYGOID
Origin :
Superficial head – maxillar tuberosity
Deep head – From lateral pterygoid plate ( medial surface ).
Insertion :
adjoining ramus of mandible , mandibular foramen ( below and behind ) , mylohyoid groove.
Action :
Elevation of mandible, protrude mandible.
Nerve supply :
Nerve to the medial pterygoid ( branch of main trunk of mandibular nerve ).
HERE IS THE END OF THE MUSCLE OF MASTICATION.
CAN REFER MY NEXT POST FOR FACIAL MUSCLE
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