muscles of mastication :) Flashcards
how is the mandible connected to the skull
synovial joints
what is the zygomatic arch or
attachment for masseter
parts of the mandible
body ramus angle coronoid process condylar process (head and neck)
what hole is in the body of the mandible
mental foramen
what is the coronoid process for
site of attachment to temporalis
what is the temporomandibular joint made from
underside of temporal bone
head of condyle
what are main parts of the temporal bone that relates to the TMJ
concave glenoid cavity
convex articular eminance
when is the joint stable
when the condyle is in the glenoid
when is the joint unstable
when the condyl is on the articular eminence
how would you depress the mandible
condyle needs to move out of the genie cavity
TMJ movments
rotation
sliding
how does sliding movements occir
head of condyle moves from glenoid cavity to articular eminance
how does rotation occur in the TMJ
through axis of condyle
what are the TMJ surfaces covered by
fibrocartilage (Articular disks)
how is the joint separated into two cavites
by articular disk
what is the articular disk attached to
lateral pterygoid
function of articular disc
attaches lateral pterygoid to posterior aspect of joint stablises joint (pulled forward to pack space when condyle on articular eminence)
is the articular disc essential
no
joint will still fuction
what causes clicking sound of the joint
disc snaps into position rather than sliding
lateral pterygoid
divided into 2 heads (attach)
upper head to disc
lower head to neck of condyle
originates from lateral side of pterygoid plate
what is the lateral pterygoid involved in
protrusion of mandible
pulls on neck of condyl out of GC
upper head contracts and pulls AD onto AE
main ligament of TMJ
temporomandibular ligament
prevents lateral displacement
accessory ligaments of TMJ
stylomandibular
sphenomandibular
what do the accessory ligaments do
define range of moment of TMJ
perceive pain
how are the right and left TMJs connected
by mandible
how many muscles in mastication
4 pairs
what are the superficial muscles of mastication
masseter
temporalis
what are the deep muscles of mastication
medial and lateral pterygoid
what are the muscles of mastication supplied by
motor branches of trigeminal v3
what are other muscles involved in movement of mandible
suprahyoid
infrahyoid
temporalis
fan shaped
fibres all come together at same place to form tendon
what is temporals attached to
lateral aspect of skull
coronoid process of mandible
where does temporals inser
anterior border of rams to retromolar fossa
what does temporalis do
elevator and retractor of mandible
what happens if dentures extend into retromolar fossa
denture displacement
masseter function and attatchments
elevator
zygomatic arch
along lateral aspect of mandibular ramus
what is the lateral pterygoid plate for
site of attachment for lateral/medial pterygoid muscles
lateral pteryoid function and attachments
protrudes mandible
lateral side of pterygoid plate and neck of condyl
medial pterygoid function and attachemnts
elevator
medial side of lateral pteryhoid plate and inner aspect of angle of mandible
what muscles elevate the mandible
temporalis
masseter
medial pterygoid
what retracts the mandible
temporalis
what protrudes the mandible
lateral pterygoids
what can the supra hyoid muscles do
pull down on the mandible by contraction
what do buccinator do
push food back into OC
what does obicularis oris do
shuts the mouth
what is lateral excursion
mandible swings side to side
how does lateral excursion occur
when mandible protrudes, lateral pterygoid of other side deviates
opposite condyle moved slightly back by temporals
what way can the TMJ dislocate
anterioally
what prevents other forms of TMJ dislocation
bony ligamentous constraints
how does dislocation of TMJ occur
condyle overrides articular eminence
how to reset TMJ
downwards backwards pressure on molars
muscle relaxants if muscles gone into spasm
what is required for incision
mandible suppressed for size of object
mandible protruded so incised edges meet
what is required for mastication
depressed for food to get between molars
deviated laterally to bring molars into cusp contact
range of movemtn
extreme when yawning
speech
what is most TMJ disfunction due to
over closing and grinding
TMJ relies on proprioception from receptors and lateralpterygoid (muscle of mastication )
