TMJ

Question 1

describe the articular disc

Answer 1

Fibrocartilaginous
Plays a primary role in stability of the TMJ
Middle portion of the disc is avascular and aneural
Anterior and posterior parts are innervated
Medial and lateral components of the disc are stabilized by collateral ligaments

Question 2

what purpose does the posterior ligament serve

Answer 2

Posterior ligaments (bilaminar zone)
Limits severe opening
Nutritional function of the joint
The fibrous joint capsule
Superior stratum attaches to the posterior mandibular fossa
Allows disc to translate forward

Question 3

Bilaminar Zone

Answer 3

Intercapsular mass of soft tissue between the superior and inferior strata
Very vascular
Well supplied with nerve endings
Supplies the condyle as well as the ear
Tinnitus 
Note: proximity of eat to TMJ

Question 4

what part of the TMJ joint is the weakest??

Answer 4

Anterior structures
Weakest part of the joint
Anterior fibrous capsule connects to the anterior portion of the disc
Superior head of the lateral pterygoid attaches anterior and medially on the disc

Question 5

what is the main ligament responsible for the suspension of the mandible

Answer 5

Lateral aspect
Temporomandibular ligament
Main ligament responsible for suspension of the mandible
Restricts backward and lateral movements
Guides the arthrokinematic motion of the joint
Can be strained with excessive downward motion, such as from a occlusal fulcrum from a molar
Ex: mouth up for 40 min at the dentist…cap put on and now it makes a fulcrum

Question 6

what strains the LCL what motion

Answer 6

Lateral
Fibrous capsule
Lateral collateral ligament
Stabilizes the disc
Medial displacement of the disc will strain the LCL

Question 7

Medial ligament is taught during what motion

Answer 7

Sphenomandibular ligament

Suspends the manible and is taut in terminal opening

Question 8

what ligament prevents extreme opening of the mouth??

Answer 8

Medial
Stylomandibular ligament
Limits extreme opening—the stopper
The MCL stabilize the disc on top of the condyle
Medial displacement of the condyle with lateral disc displacement, as seen with crossbite, can strain these ligaments

Question 9

the synovials probably not that important

Answer 9

Highly vascular and well innervated connective tissue that lines the upper and lower joint compartments of the TMJ
Produces synovial fluid
Important proprioceptive roles

Question 10

What does the temporalsis due and is ti responsible for headaches

Answer 10

Temporalis
Origin: Temporal fossa
Insertion: Coronoid process and ant. border of ramus
Function: Bilateral=elevation; unilateral=deviates mandible to same side; retract mandible, and guides biting motion
Potential for headaches or cranio fascial pain

Question 11

what actions does the masseter do??

Answer 11

Masseter (con’t)
Function: Initiates elevation of the mandible and adds force to closure
Contributes to clenching and grinding

Question 12

what does the lateral pterygoid muscle do??

Answer 12

Lateral pteryoid
Function: Mandibular depression as it pulls the condyle and disc forward (inferior head)
Stabilizes the condylar head and disc against the articular eminence during closing (superior head)
Both heads perform side to side movement, such as grinding

Question 13

what does the medial ptyergoid do??

Answer 13

Function: elevates mandible, limits protrusion when mandible is depressed, deviates mandible to one side unilaterally, and participates in chewing motion

Question 14

what does the diagastric muscle do??

Answer 14

Function: If the hyoid is fixed, it pulls the mandible back and down and functions during retrusive and opening movements

Question 15

what is the 4;1;1 realtionship about and what 3 planes does the mandible move in??

Answer 15

3-planes of movement
Opening
Lateral excursion
Protrusion
There is a 4:1:1 relationship
For every 4mm of opening, we should have 1mm of lateral excursion and 1mm of protrusion

Question 16

Biomechanics what does the articular disc help with in the TMJ.

Answer 16

The articular disc
The 2 bony surfaces of this joint are both convex, leading to an unstable joint. A biconcave articular disc in the TMJ provides both stability and prevents wear of the articular cartilage

Question 17

how much is normal opening of the mouth?? and what degree does rotation usually occur??

Answer 17

Arthrokinematics
Normal opening is 35-40mm
First 12mm is primarily a rotation
Condyle moves anteriorly and disc moves posteriorly relative to each other
As the temporomandibular lig. gets taut, disc and condyle move as one by means of translation
Terminal opening: condyle translates forward and downward on the eminenc

Question 18

what is the tounges primary role??? and how many times do we swallow a minute when not eating or drinking

Answer 18

Tongue
Primary role is swallowing
During normal swallowing, the teeth are in occlusion, the tongue slightly in front of the resting position with the muscles of mastication contracting strongly.
We typically swallow 1 time per minute when not eating or drinking

Question 19

how does a forward head affect the path of opening

Answer 19

Forward head posture:
Affects path of opening and closing
Affects the amount of muscle work involved
Affects ROM of both the TMJ and C-spine
Ex: Mean amount of opening increases by 8.3mm when comparing a forward head from a retracted head posture
Same holds true for shoulder ROM with T-spine

Question 20

what else does the forward head posture do!!

Answer 20

Forward head posture results with an increased distance between the chin and sternum, stretching the hyoid muscles
This results in pulling the mandible back and down
This increases activity of the masticatory muscles and cranial extensors
Possible cause of pain

Question 21

Pathological causes of pain

Answer 21

Degenerative changes-loss of fibrocartilage

Inflammation

Question 22

possible ligamentous can cause problems to the disc!!!

Answer 22

Ligamentous lesion
Overstretch
Continuous strain
LCL strain
MCL strain
Posterior ligament strain
Retrodiscitis-repetitive trauma to the insertion of the posterior ligament on the disc
Temporomandibular ligament strain

Question 23

desribe the capsular pattern of the jaw.

Answer 23

Capsular pattern
Consists of vertical capsular retraction, prevents distraction (downward movement) of the condyle
Constriction of the capsule can result in loss of condylar-vertical height due to a displaced disc, which as a result causes a posterior and superior displacement of the condyle

Question 24

what are somethings that could cause muscle tendon pain

Answer 24

Masseter: clenching in maximum occlusion with parafunction
Posterior temporal tendinitis: hypermobility resulting in excessive anterior translation of the condyle, impinging on the tendon, sustained excessive opening of the mouth
Suboccipital/shoulder girdle pain: due to craniomandibular parafunction; decreased craniocervical angle

Question 25

casues of subluxations

Answer 25

Can occur in the frontal and sagittal plane; usually at the same time
Subluxation are identified by 4 phases, where phase 4 is a luxation
Joint sounds, such as a “click” are commonly heard or palpated , with or without pain
Causes of subluxation are trauma, surgery, or hypermobility

Question 26

signs of OA

Answer 26

Osteoarthritis:
Bruxism and clenching of teeth
Dentition factors
Women>Men (3rd-4th decade)
Trauma
Stiffness after rest
Grating sounds are associated with DJD

Question 27

other signs of RA

Answer 27

Other joints are typically affected first
Sx: severe pain and limited ROM
Anterior open bite with molar contact is one of the first Sx due to mandibular shortening due to erosion of the articular head

Question 28

Other possible signs of TMJ

Answer 28

Other possible causes of TMD:
A hit to the mandible, possibly due to a punch or fall; sports
Look for a scar on the chin: always a give away

Question 29

reasons for TMD

Answer 29

Extraction of a molar (fulcrum effect)
Parafunction
Bad oral habits 
Poor posture
Ex: Supporting your head with your hand under your chin or plain forward head posture

Question 30

commonly located areas of pain

Answer 30

Commonly located at the muscles of mastication (maseter, sub occ, temporalis)
Also pain is felt periaural, occipital, or periocular

Question 31

How to tell if the symptoms are neruological or just plain old TMJ

Answer 31

If Sx are neurological, such as with trigeminal neuralgia, Sx are unilateral
Referred pain to the neck and shoulder girdle are common
Cervicogenic headaches are present in 50% of patients

Question 32

neuro pain how long can it last for??

Answer 32

Trigeminal Neuralgia: severe facial pain that can last seconds to 2 minutes

Question 33

how to tell if the TMD is caused by pain!!

Answer 33

Muscular pain: dull and aching
Low grade and typically intermittent
Can have a painful restriction of ROM
Due to hyperactivity of the muscles of mastication and how it can cause compression (it gets tight)

Question 34

some other symptoms of TMJ

Answer 34

Ears: tinnitus and stuffiness

Very common

Question 35

what are some reasons for TMJ

Answer 35

Due to:
STRESS!!!!!!!
Hx of tooth extractions
Hx of clenching and grinding
Hx of nail biting
Many patients have undergone orthodontic care or appliance therapy

Question 36

how to look for facial asymmetry

Answer 36

Facial asymmetry
Divide the face for inspection
are top teeth alligned witintthe bottom teeth lifting up the lip

Question 37

Look at the pain map

Answer 37

Pain #1,5, and 8 are due to compression by the condyle
Pain #2 and 6 are related to the disc
Pain #1 and 3 are related to the condyle