Transcript Muscle of mastication

Muscle of mastication
Mandibal moves with the help of muscle of
mastication there are four main pairs of
muscles and they are
1-Massetor muscle
2-Temporalis muscle
3-Medial Partygoid
4-Leteral petrygoid
e
most power ful
Masseter Muscle
• It is the most superficial and powerful muscle of
mastication it is quadrilateral in
shape
• Origen: it is origin is from the inferior and medial
surface of Zygomatic bone and temporal
process of zygomatic bone from here it extends
downwards and posterior
• Insertion : lateral surface of the Ramus ,angel
and lower border of the mandibale
• Action: it acts as an Elevator .it closes the jaw
and applies great power in crushing food
Temporalis muscle
• It is like fun-shaped, large and flat muscle
• Origin : from temporal fosse from here the fibers
are directed downwards and interiorly
• Passing medial to the zygomaticarch
• Insertion: to the coronoid proess of the
mandibale,anterior border of the ramus and
temporal crest of the mandibale
• Action: anterior fibers contract and elevates the
mandibale to close the jaw
• Posterior most horizental fibers retract or pull
the jaw backwards
Medial pterygoid muscle
• This muscle is located medial to the ramus
of the mandibal
• Origin: from the medial surface of the
lateral pterygoiod fosse B/w the medial
and lateral plates OF sphenoid bone the
fibers pass downward and laterally
towards the angle of the mandibale
Action
• it elevator it is synergist of the masseter
muscle
• Lateral pterygoid muscle
• This muscle is a short,thick,conical and is
located deep in the infratemporal fosse it’s
prime mover of the mandibale except for
closing the jaw
Origin
• : it has two heads smaller upper head and
large lower head
• The upper head originates from the
infratemporal surface on the greater wing
of sphenoid bone the large lower head
originates from the lateral side of the
lateral pterygoid plate on sphenoid bone
Insertion
• Upper head attaches to the front of the neck of
the condyloid
• process and to the anteriomedial surface of the
condyle
• lower head attaches to the despression on the
front of the neck of the condyle
• into the particular capsule and disk TMJ fibers
of lateral pterygoid muscle run anterior
posteriorly
•
Action
• both heads of the fibers contract
simultaneously to open the jaw ,protrude
the jaw anteriorly and lateral movements
of the jaw