Mastication and muscles of mastication Flashcards

1
Q

What are the chief muscles of mastication

A
  • Masseter muscle
  • Temporalis muscle
  • Medial pterygoid muscle
  • Lateral pterygoid muscle
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2
Q

Which is the larger head of the masseter muscle

A

Superficial

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3
Q

What is the origin and insertion point of the superficial masseter

A

Origin - anterior two-thirds of the lower border of the zygomatic arch.
Insertion - the angle and lower half of the lateral surface of the ramus of the mandible.

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4
Q

Which direction do the fibres of the superficial masseter run

A

downwards and backwards

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5
Q

What is the origin point of the deep masseter

A

Origin: it arises from the posterior third of the lower border and from the whole of the medial surface of the zygomatic arch.

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6
Q

What is the insertion point of the deep masseter

A

the upper half of the ramus

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7
Q

Which direction do the fibres of the deep masseter run

A

down and forwards

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8
Q

Anteriorly and posteriorly what is the deep masseter related to

A

Ant: superficial portion
Post: the parotid gland

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9
Q

What are the actions of the masseter

A

elevates and protrudes the mandible thus

closing the mouth; deep fibers retrudes it.

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10
Q

What innervates the masseter

A

Mandibular division (V3) of trigeminal nerve through masseteric branch.

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11
Q

What is the blood supply of the masseter

A

masseteric artery from maxillary

artery

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12
Q

What is the origin point of the temporalis

A

the whole of the temporal fossa and the deep surface of temporal fascia

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13
Q

What is the insertion point of the temporalis

A

the medial surface, apex, and anterior border of the coronoid process, and the ant. Border of mandibular ramus

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14
Q

What is the action of the temporalis muscle

A

its anterior and middle fibers elevate the mandible thus closing the mouth; its posterior fibers retrudes it.

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15
Q

What innervates the temporalis muscle

A

Deep temporal branches of mandibular nerve.

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16
Q

What supplies blood to the temporalis muscle

A

Deep temporal branches of maxillary artery.

17
Q

What are the 2 heads of the lateral pterygoid muscle

A

superior and inferior

18
Q

What is the origin point of the lateral pterygoid muscle

A

the superior head arises from greater wing of sphenoid bone while the inferior head arises from the lateral surface of the lateral pterygoid plate

19
Q

What is the insertion point of the lateral pterygoid muscle

A

fibers pass backward to be inserted into the neck of mandible and articular disc of TMJ.

20
Q

What innervates the lateral pterygoid muscle

A

Ant. division of mandibular nerve through lateral pterygoid nerve

21
Q

What supplies blood to the lateral pterygoid muscle

A

maxillary artery through the pterygoid branch.

22
Q

What is the action of the lateral pterygoid muscle

A

acting together they protrude and
depress the mandible;
acting alone and alternatively they produce side to side movements of the mandible.
(rotates the mandible to the opposite side)

23
Q

What are the heads of the medial pterygoid muscle

A

superficial and deep

24
Q

What is the origin point of the medial pterygoid muscle

A

the superficial head arises from the maxillary tuberosity. The deep head arises from medial surface of the lateral pterygoid plate

25
What is the insertion point of the medial pterygoid muscle
the medial surface of the angle of the mandible
26
Which direction do the fibres of the medial pterygoid muscle run
backward, laterally and downwards
27
What innervates the medial pterygoid muscle
main trunk of mandibular nerve through nerve to medial pterygoid
28
What supplies blood to the medial pterygoid muscle
Maxillary artery through the medial pterygoid artery
29
What is the action of the medial pterygoid muscle
Assists in elevating and protrusion of the mandible Acts together with lat. Pterygoid of the same side in rotating the mandible
30
What are the origin and insertion points of the digastric muscles
``` origin = mandible process insertion = mastoid process ```