Download Muscles of Mastication LO6

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Muscles of Mastication LO6
6. For each of the following muscles state its innervation and apply principles M4-M7 to
describe its attachments and actions:
Muscle
Muscles of Mastication
Temporalis
Origin
Insertion
Innervation
Position & Orientation
Function
Temporal fossa
Coronoid process
of mandible
Mandibular division
of trigeminal nerve
(CN V3)
Triangular muscle with
vertical fibers at the front
and horizontal fibers at
the back.
All fibres: elevation of mandible at
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TMJ
Temporal fascia
Anterior border of
ramus of mandible
Posterior: retraction of the
mandible at TMJ
Often separated into
anterior, middle and
posterior fibers
Masseter
Medial surface
and inferior
border of
zygomatic bone
Lateral surface
and ramus and
angle of mandible
Mandibular division
of trigeminal nerve
(CN V3)
Quadrate muscle
Elevates mandible at TMJ joint
Oblique fibers that are
almost vertical!
Makes a limited contribution to
protrusion at TMJ along with lateral
pyerygoid
Medial surface of Medial surface of
lateral pterygoid ramus and angle
plate
of mandible
Mandibular division
of trigeminal nerve
(CN V3)
Mirror image of ipsilateral Bilateral: elevation and protraction
masseter.
of mandible at TMJ
Zygomatic arch
Medial pterygoid
Lateral pterygoid
Lateral surface of Superior head:
lateral pterygoid TMJ articular disc
plate
TMJ joint capsule
Mandibular division
of trigeminal nerve
(CN V3)
Oblique fibers that are
almost vertical!
Unilateral: smaller grinding
movements
Transverse fibers
Bilateral: Protraction and
depression of mandible at TMJ
Inferior head:
Neck of mandible
Masseter and temporalis muscles both have long leaver arms which increases the
mechanical advantage of these muscles. Enables them to produce force up to 80N!!
Unilateral: lateral displacement
(swings jaw towards contralateral
side) at TMJ
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Suprahyoid Muscles
Digastric
Base of cranium
Mastoid process
Facial and
mandibular nerves
Anterior and posterior
muscle bellies
Depresses mandible against
resistance when infrahyoid muscles
fix hyoid bone
Fixed to hyoid by sling
Geniohyoid
Mylohyoid
Anterior body of
the posterior
surface of the
mandible
Medial body of
the posterior
surface of the
mandible
Hyoid bone
Nerve to geniohyoid
Hyoid bone
Mandibular nerve
Depresses mandible against
resistance when infrahyoid muscles
fix hyoid bone
Forms the floor of the oral
cavity
Depresses mandible against
resistance when infrahyoid muscles
fix hyoid bone
Accessory muscles of mastication because can only act on the mandible in combination with the
infrahyoid muscle which stabilize the hyoid bone.
Jesse Wilson 17394150
Jesse Wilson 17394150
Jesse Wilson 17394150
Actions of Primary Muscles of Mastication