TMJ

Question 1

TMD incidence

Answer 1

• 50-70% of population experiences U/L TMD at least on 1 occasion
• 33% of population report continuing symptoms
• 5% of population pursue medical care
• Women>men

Question 2

what is TMD assoicated with

Answer 2

• jaw grinding or clenching (bruxing)
• TMD is multifactorial: realted to physical, functional and psychological disorders
• no gold standard to detect TMD

Question 3

TMD exam clinical findings

Answer 3

• joint sounds
• limitations of jaw movements
• hypermobility
• pain: joint, capsule/ligaments, disc dysfunction, muscle overuse

Question 4

TMD classifications

Answer 4

• inflammatory disorders: OA, RA (hyper/hypomobility)
• disc disorders: disc positional changes (derangement-reducing and nonreducing)
• muscle/myofascial pain: overuse

Question 5

TMD diagnostics

Answer 5

• MRI: most accurate to identify disc disorder, OA, RA
• also X-ray, CT scans, MSK US
• DX tests have little value detecting myofascial pain
• arthroscopy used to detect and treat a disc derangement

Question 6

Ligaments of the TMJ

Answer 6

• joint capsule
• lateral temporomandibular ligament: limits excessive opening

Question 7

Arthrology of the joint

Answer 7

• posterior glenoid process: prevents condyle from going too far posterior
• articular eminence: prevents condyle from going too far anterior

two joint spaces

• superior joint space
• inferior joint space

Question 8

TMJ Disc and attachments

Answer 8

• posterior bands: superior and inferior attach to disc, enclosed retro-discal fat pad
• lateral pterygoid superior head attaches to disc
• anterior capsule has attachment to anterior disc

Question 9

TMJ movements in superior and inferior joint spaces

Answer 9

• 1st condyles rotate in inferior joint space
• 2nd disc/condyle complex translation in superior joint space

Question 10

TMJ innervation

Answer 10

• mandibular branch of trigeminal nerve
• mandibule nerve = motor to muscles of mastication, sensory to temptoral region of ear, jaw/cheeck, teeth and tongue
• auriculotemporal n: branch of mandibular n recieves snesory innervation from TMJ capsule, TMJ ligaments, retro-discal fat pad

Question 11

TMJ osteo/arthrokinematics: opening

Answer 11

• opening normal 35-55 mm
• suprahyoids with stabilization from infrahyoids
• phase 1: condyles rotate on disc in lower joint space
• phase two condyle/disc translates anterior in upper joint space
• posterior bands prevent disc from going too far anteriorly

Question 12

TMJ

Osteo/arthrokinematics: closing

Answer 12

• temporalis, massester, medial pterygoid
• phase 1: condyles rotates in lower joint space
• phase 2: condyles/disc translates posterior in upper joint space
• upper head lateral pterygoid (tension) prevents disc from going too far posteriorly

Question 13

TMJ osteo/arthrokinematics

protrusion/retrusion

Answer 13

protrusion

• medial and lateral pterygoid working B/L
• translates anterior in upper joint space (3mm)

retrusion

• temporalis B/L draws mandible backward with massester assisting

Question 14

Lateral shifting of the TMJ

Answer 14

• 12 mm
• ipslateral condyle rotates = temporalis, massester
• contralateral condyle translates anterior = lateral and medial pterygoids

Question 15

Explain how lateral shifting is affected with a right sided hypomobile

Answer 15

• L ipsilateral condyle spins
• L temporalis and massester cause rotation
• R contralateral condyle translates anterior
• med/lat pterygiod translates R mandible anterior

if R is hypomobile the right cant translate anterior to allow lateral shift to left

Question 16

TMJ hypomobility

Answer 16

• opening < 35mm
• capsular tightness bilateral - immobilization, post jaw fracture, jaw wiring
• unilateral hypomobility: opening = deviation to hypomobile Side - gives C curve due to unable to translate forward on hypo side

Question 17

TMJ Hypermobility

subluxation

factors that increase this risk

Answer 17

• stretched TMJ capsule, ligaments
• anterior articular eminence is flatter and smaller
• condyle translates too far anterior onto articular eminence
• if U/L hypermobility jaw deflexs to opposite side the relative tighter side

Question 18

TMJ hypermobility

dislocation

Answer 18

• trauma to jaw
• condyle slides over disc, disc acts as block
• jaw cant close
• mouth is open and deflected toward contralateral side
• can be someone who is really hypermobile- EDS

Question 19

TMJ pathology

synovitis/capsulitis

Answer 19

• inflammation and pain
• bruxing, grinding, gum chewing, overuse

Question 20

TMJ pathology

Traumatic arthritis

Answer 20

• post trauma or injury

Question 21

TMJ pathology

OA/RA

Answer 21

• condyle, glenoid fossa, disc
• OA = crepitis, radiographic degeneration changes, osteophyates
• RA: joint erosion, ligament/capsular laxity, hypermobility

Question 22

TMJ pathology

disc derangement

Answer 22

• displacement
• anteriorly displaced disc
• click w/ opening and closing as condyle slides over disc

Question 23

TMJ pathology

Answer 23

• synovitis/capsulitis
• traumatic arthritis
• OA/RA
• disc derangment
• MMD

Question 24

Normal posture resting position of TMJ

Answer 24

in proper C/S posture:

• head and neck in good alignment
• TMJ is in proper resting position
• tongue in light contact with roof of mouth
• there is no occlusal contact between teeth called freeway space
• there is minimal muscle activity
• a resting tone in jaw opening and jaw closing muscles

Question 25

what happens with the TMJ joint in forward head position

Answer 25

• jaw drops
• jaw recedes
• gravity applies tension
• changes the position of the condyle with the joint

Question 26

MMD: masticatory muscle disorder

Answer 26

• TMJ and muscle pain due to
• bruxing/grinding teeth,
• muscles over worked
• increase muscle tone/spasm => compression of TMJ joint
• myofascial trigger points in temporalis and masseter

Question 27

MMD

treatment

Answer 27

• correct posture - C/S retraction
• massage/STM
• appliance from bruxing/grinding