Muscle of mastication
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Transcript of Muscle of mastication
MUSCLE OF MASTICATION
Riddhi Dave
MUSCLE OF MASTICATION There are main FOUR muscle which are
involved in mastication. 1) TEMPORALIS 2) MASSETER 3) LATERAL PTERYGOID 4) MEDIAL PTERYGOID
MUSCLE ATTEACHMENT TO THE MANDIBLE
TEMPORALIS MUSCLE
INTRODUCTION Temporalis muscle is fan shape muscle. It fills the temporal fossa.
ORIGIN Temporal fossa excluding the zygomatic
bone. Temporal fascia.
FIBERS Anterior fibers run vertically. Middle fibers run obliquely. Posterior fibers run horizontally. All converge and pass through gap deep to
zygomatic arch.
INSERTION Margins and deep surface of coronoid
process. Anterior border of ramus of mandible.
NERVE SUPPLY Two deep temporal branches from
anterior division of mandibular nerve.
ACTION Elevates mandible Helps in side to side grinding movement Posterior fibers retract the mandible
MASSETER MUSCLE
INTRODUCTION It is quadrilateral in shape. It is antigravity muscle. It covers the lateral surface of ramus of
mandible, and it has two layers.
ORIGIN Superficial layer(largest) :- from anterior
2/3 rd of lower border of zygomatic arch and adjoining zygomatic process of maxilla.
Deep layer(small) :- from deep surface of zygomatic arch.
FIBERS Superficial fibers pass downwards and
backwards at 45 degree. Deep fibers pass vertically downwards.
INSERTION Superficial layer :- into lower part of
lateral surface of ramus of mandible. Deep layer :- into rest of the ramus of
mandible.
NERVE SUPPLY Masseteric nerve
ACTION Elevates the mandible to close the
mouth for bite.
LATERAL PTERYGOID
INTRODUCTION Short , conical muscle. It has two heads upper and lower head.
ORIGIN Upper head(small) :- from infratemporal
surface and crest of greater wing of sphenoid bone.
Lower head(larger) :- from lateral surface of the lateral pterygoid plate.
FIBERS Fibers run backward and laterally and
converge for insertion.
INSERTION Pterygoid fovea on the anterior surface
of neck of mandible. Anterior margin of articular disc and
capsule of TMJ.
NERVE SUPPLY Nerve to lateral pterygoid branch of
mandibular nerve.
ACTION Depresses mandible to open mouth with
suprahyoid muscle. Lateral and medial pterygoid protrude
mandible. Right lateral and medial pterygoid
muscle turn the chin on left side as part of grinding movements.
MEDIAL PTERYGOID
INTRODUCTION It is a quadrilateral muscle. It has small superficial and large deep
muscle.
ORIGIN Superficial head :- from tuberosity of
maxilla and adjoining bone. Deep head :- from medial surface of
lateral pterygoid plate.
FIBERS Fibers run downwards , backwards and
laterally.
INSERTION Roughened area on the medial surface of the
angle and adjoining ramus of mandible, below and behind the mandibular foramen and mylohyoid groove.
NERVE SUPPLY Nerve to medial pterygoid which is a branch of
the main trunk of mandibular nerve.
ACTION Elevates the mandible Protrude the mandible Right lateral and medial pterygoid muscle turn
the chin on left side as part of grinding movements.
RELATIONS OF MEDIAL PTERYGOID MUSCLE SUPERFICIAL RELATIONS Lateral pterygoid plate Lingual nerve Inferior alveolar nerve
DEEP RELATIONS Tensor veli palatini Superior constictor of pharynx Styloglossus