Mastication and muscles of mastication Flashcards
What are the chief muscles of mastication
- Masseter muscle
- Temporalis muscle
- Medial pterygoid muscle
- Lateral pterygoid muscle
Which is the larger head of the masseter muscle
Superficial
What is the origin and insertion point of the superficial masseter
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.
Which direction do the fibres of the superficial masseter run
downwards and backwards
What is the origin point of the deep masseter
Origin: it arises from the posterior third of the lower border and from the whole of the medial surface of the zygomatic arch.
What is the insertion point of the deep masseter
the upper half of the ramus
Which direction do the fibres of the deep masseter run
down and forwards
Anteriorly and posteriorly what is the deep masseter related to
Ant: superficial portion
Post: the parotid gland
What are the actions of the masseter
elevates and protrudes the mandible thus
closing the mouth; deep fibers retrudes it.
What innervates the masseter
Mandibular division (V3) of trigeminal nerve through masseteric branch.
What is the blood supply of the masseter
masseteric artery from maxillary
artery
What is the origin point of the temporalis
the whole of the temporal fossa and the deep surface of temporal fascia
What is the insertion point of the temporalis
the medial surface, apex, and anterior border of the coronoid process, and the ant. Border of mandibular ramus
What is the action of the temporalis muscle
its anterior and middle fibers elevate the mandible thus closing the mouth; its posterior fibers retrudes it.
What innervates the temporalis muscle
Deep temporal branches of mandibular nerve.
What supplies blood to the temporalis muscle
Deep temporal branches of maxillary artery.
What are the 2 heads of the lateral pterygoid muscle
superior and inferior
What is the origin point of the lateral pterygoid muscle
the superior head arises from greater wing of sphenoid bone while the inferior head arises from the lateral surface of the lateral pterygoid plate
What is the insertion point of the lateral pterygoid muscle
fibers pass backward to be inserted into the neck of mandible and articular disc of TMJ.
What innervates the lateral pterygoid muscle
Ant. division of mandibular nerve through lateral pterygoid nerve
What supplies blood to the lateral pterygoid muscle
maxillary artery through the pterygoid branch.
What is the action of the lateral pterygoid muscle
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)
What are the heads of the medial pterygoid muscle
superficial and deep
What is the origin point of the medial pterygoid muscle
the superficial head arises from the maxillary tuberosity. The deep head arises from medial surface of the lateral pterygoid plate
What is the insertion point of the medial pterygoid muscle
the medial surface of the angle of the mandible
Which direction do the fibres of the medial pterygoid muscle run
backward, laterally and downwards
What innervates the medial pterygoid muscle
main trunk of mandibular nerve through nerve to medial pterygoid
What supplies blood to the medial pterygoid muscle
Maxillary artery through the medial pterygoid artery
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
What are the origin and insertion points of the digastric muscles
origin = mandible process insertion = mastoid process
