LECTURE 4- TMJ Flashcards by Chavez Girls

what are the main 2 articular structures that make up the TMJ

mandible and temporal

How well did you know this?

Not at all

Perfectly

other bones contributing to the TMJ structure

maxilla , zygomatic , sphenoid, hyoid

How well did you know this?

Not at all

Perfectly

what forms the 2 TMJs

condole of mandible and articular eminence of temporal

How well did you know this?

Not at all

Perfectly

what type of joint is the TMJ

synovial joint

How well did you know this?

Not at all

Perfectly

are the surfaces of the TMJ covered in fibrocartilage or hyaline cartilage?

avascular fibrocartilage

How well did you know this?

Not at all

Perfectly

what type of movement joint is the TM joints

ginglymoarthrodial (diarthrosis) allowing for free movement

How well did you know this?

Not at all

Perfectly

which layers of the joint surfaces are perpendicular to bony surface and what do they do

deep layers and withstand stress

How well did you know this?

Not at all

Perfectly

how are the superficial layers of the joint surfaces arranged and what do they facilitate in the TMJ

parallel and facilitate sliding of joint

How well did you know this?

Not at all

Perfectly

how much can a bite force be

up to 1200 N

How well did you know this?

Not at all

Perfectly

what structure is the largest of facial bones

mandible

How well did you know this?

Not at all

Perfectly

where do the mandible condyles sit in relation to the ear

anterior to external auditory meatus

How well did you know this?

Not at all

Perfectly

what part of the mandible is the attachment site for temporalis muscle

coronoid process

How well did you know this?

Not at all

Perfectly

what makes up for joint incongruence and separates articulation into inferior and superior TMJ functions

articular disc

How well did you know this?

Not at all

Perfectly

how does the inferior TMJ function (type of joint and motion)

as an hinge joint - rolling posterior during opening

How well did you know this?

Not at all

Perfectly

how does the superior TMJ function

as a plane joint , sliding anterior during opening

How well did you know this?

Not at all

Perfectly

the articular disc of the TMJ is what shape?

bioconcave

How well did you know this?

Not at all

Perfectly

what purposes do the articular disc of the TMJ serve

joint stability
minimize loss of mobility
reduce frication
decrease biomechanical stress at joint

How well did you know this?

Not at all

Perfectly

where does the disc attach at the TMJ? what bony landmarks

medial and lateral poles of the mandible condyle
the bilaminar retrodiscal pad (posterior)
joint capsule and tendon of lateral pteryoid muscle (anteriorly)

How well did you know this?

Not at all

Perfectly

what do superior and inferior lateral pterygoid muscle restrict ?

posterior translation

How well did you know this?

Not at all

Perfectly

what does the superior lamina allow the disc to do

translate anteriorly by stretching

How well did you know this?

Not at all

Perfectly

what does the interior lamina limit

forward translation

How well did you know this?

Not at all

Perfectly

what is the articular disc of the TMJ made up of

can it remodel?

collagen , proteoglycans , and elastin

How well did you know this?

Not at all

Perfectly

what is the vascularity of the anterior band of the disc and where does it attach to

minimal to no vascular supply and attaches to joint capsule anteriorly

How well did you know this?

Not at all

Perfectly

what is the vascularity of the intermediate zone of the disc and where does it attach to

no vascular supply and attached to medal and lateral condyle of mandible

How well did you know this?

Not at all

Perfectly

what is the vascularity of the posterior band of the disc and where does it attach to

rich innervation and vascular supply from retrodiscal tissue and attached to retrodiscal tissue which is attached to capsule

where is the capsule for TMJ the stronger

laterally

what is the vascularity of the capsule forTMJ

highly vascular and innervated

3 ligaments of the TMJ

TM lig stylomandibular lig sphenomandibular lig

what does the oblique TM lig do

limits downward and posterior motion/ rotation of mandible

what does the horizontal TM lig do

resist posterior motion of condyle

what do both TM ligs do (what movement do they resist)

resists lateral displacement

what does the stylomandibular and sphenomandibular lig do

styloid - may limit protrusion of jaw , weakest spheno - prevent foward translation

when is the TMJ engaged

mastication , swallowing and speaking

what are the arthokinematic movements of the TMJ

rolling anterior slide distraction lateral glide

what are the osteokinematic motions of TMJ

depression elevation protrusion retrusion L/R lateral excursions

what is the Normal depression ROM of the TMJ

40-50 mm 2 finger functional 3 normal

what happens 1st during normal depression

11-25 mm anterior rotation of condyle on disc which leads to posteior roll of mandible

what happens 2nd during normal depression

translation : both condyle and disc anterior and interior which leads to anterior slide of condyle

passive depression involves what

disc translate along the articular eminence and retrodiscal lamina limits translation

if there is active depression of the tmj what happens

there is no active contraction of superior lateral pterygoid

what happens passively during elevation of the mandible

elasticity of the superior retrodisc lamina apples traction force posteriorly

during active elevation of what eccentrically contracts to control posterior gliding and rotation of condyle

superior lateral pterygoid

what 3 muscles provide contrast pressure on disc to prevent dislocation during elevation

temporalis , medial pterygoid and masseter cant win them all its ok

where do protrusion and retrusion occurs - superior or inferior joint of TMJ

in superior portion of the joint

what is anterior translation without rotation of inferior joint

protrusion

bilateral lamina stretch _____ to allow complete motion during protrusion

6-9mm

during protrusion teeth touching = ____ and lower teeth passing upper teeth = ___

normal max

what does retrusion do

translation posteriorly (3mm)

what is retrusion limited by

TM lig and soft tissue in retrodiscal area remember the earlier slide, TM limits posterior motion!

what is a important component of mandibular elevation from maximally depressed mandible

retrusion

what is the normal range of lateral excursion

8-11 mm

if someone does a right lateral excursion what happens at the joint

right TMJ rotation and L TMJ translation

limited right lateral excursion of the jaw, the muscles on the ____ side (especially the ___ lateral pterygoid) are likely tight or dysfunctional. This can restrict the ability to move the jaw to the right,

left

during lateral excursion there is an …

ipsilateral mandibular condyle rotation and contralateral mandibular condyle translations

what is it called if the mandible moves away from mandible during mandibular depression and stays to the L or R

deflection C CURVE

what is a deviation

when the mandible move away from mideline during depressions or protrusion but then returns to midline at end range S CURVE

what muscles help depression

digastric & suprahyoids inferior lateral pterygoid gravity DIGS

what muscles help elevation

temporalis masseter medial pterygoid superior lateral pterygoid TMMP

what muscles help assist protrusion

Bil: masseter , medial and lateral pterygoid

what muscles help assist with retrusion

bil: temporalis , assisted by anterior digastric

what muscles help with lateral deviation

unilateral contraction of medial and lateral pterygoids to pull to contralateral side ( R medial and lateral will pull to L) temporalis will pull to ipsilateral side

what are considered secondary muscle of TMJ

diagastric muscle (anterior belly) mylohyoid stylohyoid geniohyoid

what are considered deep cervical flexors

longus colli and longus capitus

what are the bilateral and unilateral actions of the longus colli

bilateral: neck flexion uni: SB with contralateral rotations same as SCM

what is the unilateral and bilateral action for longus capitus

bilateral: neck flexion unilateral: SB with ipsilaterla rotation

what position does forward heard posture put the mandible in?

retraction of mandible after malalignment

Contact of the upper and lower teeth limits TMJ motions when the mouth is ___ (closed or open) So losing teeth would...

affect the mechanics!

Should the teeth touch during the day at rest?

maximal intercuspation

teeth are approximated occlusion position linked together maximally in normal jaw closed position

what is the freeway space of the teeth

normal rest position with 1-5 mm of space between supper and lower teeth at rest

foward head ___ freeway space

decreases

what are teh structural changes of the disc

wear and tear may lead to OA

is it possible for normal wear and tear to occur without symptoms or disfunction?

yes!

what might lead to dysfunctions of the TMJ

trauma, postural habits, oral habits, bruxism (grinding)

capsular fibrosis of TMJ will lead to

overproduction of connective tissue leading to loss of tissue function with painful movements

inflammation of TMJ will lead to

capsulitis and synovitis leading to RA

joint hyper mobility of the TMJ is when there is …

an opening over 40 mm

if you have joint hypermobility at the TMJ what will happen

there will be a deflection of mandible to contralateral side when opening

what muscle hypertrophy, atrophy, or contracture if someone has joint hypermobility

lateral pterygoid muscle

dislocation of the TMJ will cause

opening with deviation and inability to close due to anterior translated disc

if you have an articular disc displacement with reduction then what happens

the condyle is behind the disk at rest so it translates anteriorly with depression with a click and translates posterior and slips out from under the disc during elevation with a click

if you have articular disc displacement without reduction then what happens

the posterior attachments to the disc are overstretched and are unable to relocate during depression no clicking disc stays in front the whole time, and condyle never pops on it, no clicking sound, locked jaw

if you have articular disc displacement without reduction when do you have pain

chewing , talking , yawning