Muscles of mastication and ECA Flashcards
what are the muscles of mastication
temporalis
masseter
medial pterygoid
lateral pterygoid
what nerve innervates the muscles of mastication
mandibular division of the trigeminal (CN V3)
what are the movements of the mandible
elevation depression protrusion retrusion lateral sliding
what assists the muscles of mastication in depression of the mandible
gravity
supra-hyoid muscles
what is the largest muscle of mastication
temporalis
what muscle of mastication is covered by temporal fascia
temporalis
what is the function of temporalis
elevate and retract mandible
what fibres of temporalis allow elevation of the mandible (Close the mouth)
anterior and superior
what fibres of temporalis allow retraction of mandible
posterior fibres
where does temporalis sit
temporal fossa
what are the attachments of temporalis
temporal fossa and fascia to coronoid process and anterior border of the ramus of the mandible
what is the innervation of temporalis
deep temporal nerves (x2) from anterior division of the mandibular division of the trigeminal nerve (CNV3)
what are the superficial muscles of mastication
temporalis and masseter
what is the function of masseter
elevate mandible
what crosses the anterior surface of masseter
parotid duct
what is the innervation of masseter
masseteric nerve from anterior divisino of CNV3
what are the attachments of masseter
zygomatic arch to the lateral aspect of the ramus of the mandible
what are the deeper muscles of mastication
medial and lateral pterygoid
where do the medial and lateral pterygoids lie
infratemporal fossa
how many heads does lateral pterygoid have
2
why is the lateral pterygoid called the lateral pterygoid
one head attaches to the lateral surface of the lateral pterygoid plate
what are the attachments of the upper head of the lateral pterygoid
infratemporal surface of greater wing of sphenoid
what are the attachments of the lower head of lateral pterygoid
lateral surface of the lateral pterygoid plate
what is the common attachment of both heads of the lateral pterygoid
neck of mandible and articular disc
what are the attachments of lateral pterygoid
upper head from infratemporal surface of greater wing of sphenoid
lower head from lateral surface of lateral pterygoid plate
insert into neck of mandible and articular disc
what is the action of lateral pterygoid
pulls neck of mandible forwards with articular disc (protrusion = both)
helps in lateral chewing movements with medial pterygoid (one side)
what is the innervation of lateral pterygoid
nerve to lateral pterygoid - anterior division of CN V3
why is the medial pterygoid called the medial pterygoid
named after the attachment point of its deep head - medial side of the lateral pterygoid plate
what is unusual about medial pterygoid
nerve supply is from the main trunk of the mandibular division of the trigeminal nerve before it bifurcates into anterior and posterior divisions - the other muscles of mastication are supplied by the anterior division
what are the attachments of the superficial head of the medial pterygoid
tubercle of maxilla
what are the attachments of the deep head of the medial pterygoid
medial surface of the lateral pterygoid plate
what is the common attachments of both heads of the medial pterygoid
medial surface of the angle of the mandible
lateral pterygoid is named after what head
lower head
medial pterygoid is named after what head
deep
what are the attachments of the medial pterygoid
superficial head from the tubercle of the maxilla
deep head from the medial surface of the lateral pterygoid plate
insert into the medial surface of the angle of the mandible
what is the function of the medial pterygoid
assists in elevation
what is the innervation of the medial pterygoid
nerve to medial pterygoid from the main trunk of the mandibular division of the trigeminal nerve CN V3
what happens in elevation of the mandible
head of mandible and disc move backwards and head rotates on lower surface of disc
what muscles contribute to elevation of the mandible
temporalis, masseter, medial pterygoid
what happens in depression of the mandible
head of mandible rotates on undersurface of articular disc and mandible is pulled forward
what muscles contribute to depression of the mandible
lateral pterygoid digastric geniohyoid mylohyoid (gravity)
what happens in protrusion of the mandible
articular disc and head of mandible move forward - movement in upper part of cavity