Muscles Of Mastication Flashcards
Where do masticatory movements take place
The TMJ
What are some in pm bony features of the TMJ
The condyle
Glenoid flossa
Articulate eminence
What si the movement when the jaw opens
Hinge
What happens when the jaw opens widely
Hinge and slide
What happens In a protrusion
Slide Anteriorly
What happens in a lateral excursion
Working side - rotation around vertical axis
Non working side - translation
What are the four muscles of mastication
Masseter
Temporalis
Lateral and medial pterygoid
What innervates the muscles of mastication
The motor root of trigeminal nerve
What si the most powerful muscle of mastication
The masseter
What is the structure of the masseter
Quadrangle in shape split into two parts deep and superficial
What are the attachments of the masseter
Superficial originates form maxillary process of zygomatic bone
Deep part originates form zygomatic arch if temporal bone
Both parts attach a to the ramus of mandible
What are the actions of the masseter
Elevates the mandible closing the mouth
Where does the temporal bone originate
In the temporal fossa shallow depression on lateral aspect of skull
What covers the temporalis
Tough fascia this can harvested surgically and used to repair tymp mem perforated
What are the attachments of the temporalis
Originates form temporal fossa condenses to a tendon which inserts onto coronoid orocess of mandible
What are h actions of the temporalis
Elevated the mandible closing the mouth
Retracts the mandible pulling jaw Posteriorly
What is the structure of the medial pterygoid
Quadrangle muscle with a deep and superficial head
Where is the medial pterygoid located
Inferior to lateral pterygoid
What are the attachments of the medial pterygoid
Superficial head originates form maxilla
Deep head originates from lateral pterygoid
Both parts attach to ramus of mandible near angle
What si the action of the medial pterygoid
Elevates the mandible closing the mouth
What si the shape of the lateral pterygoid
Triangular shape with two heads superior and inferior
What are the muscle fibres like
Horizontal
What do the two tendons of the lateral ptery do
Converge to a single tendon which attaches to the neck of mandible
What are the attachments of the lateral ptery
Superior head originates form greater wing of sphenoid
Inferior head originates form lateral otery plate of sphenoid
What si the action of the lateral ptery
Acting bilaterally, lateral pterygoid protract the mandible pushing the jaw forwards
Unilateral action produces side to side movement of jaw
What are the 3 groups of muscles used in mastication
Between skull and mandible - muscles of mastication
Between mandible and hyoid
Hyoid stabilisers
What are the muscles between the mandible and hyoid used for mastication
Genio hyoid c1 with hypoglossal
Mylohyoid Vc
Abd Vc
What are the hyoid stabilisers
Infrahyoid
PBD
Stylohyoid
What does the trigeminal nerve motor root do
Exit brainstem at pons Carried with Vc Exit skull at formen ovale Nerves to - masseter - temporalis - med ptery - lat ptery - mylohyoid - Abd - tensor palatini - tensor tympani
What ar the physiological chewing forces
70-150n dentate
4-55n Edentulous
What are the maximum clenching forces
500-700n between molars
What si mastication
Chewing
Breakdown foodstuffs to prep for swallowing, increase sa for digestion, release chemicals for taste
Stimulate salivary flow
