Lecture 3: TMJ Flashcards
What kind of joint is the TMJ?
what are its key structures?
Movement is a combination of what?
Which pterygoid attaches to the anterior part of the disc and causes mouth opening?
Modified hinge-type synovial joint
Key structures:
-articular disc
-condyloid and coronoid process of mandible
-mandibular fossa
-zygomatic process of temporal bone
Movement: Rotates then glides. The inferior part of joint is hinge, superior part is gliding
Lateral pterygoid attaches to anterior disc
Review of the biomechanics.
Initial opening is what type of movement?
Full opening requires what?
- Initial opening is Rotational movement
- Full opening needs continues rotation with additional forward translation
how do you evaluate the TMJ?
Steps?
- Inspection- dental allignment, particular attention to any recent work
- Screening
- 3 fingers or 2 knuckle test for effective opening - Palpation (motion)
- opening and closing
- any diffiulties or pain (reduced ROM)
- any deviations
- any palpable/ audible clicks
ROM active- protract, retract, lateral deviation -lower canine lining up, if not think about what structures could be limiting these motions.
Mouth stuck closed- disc has been displaced posteriorly
Mouth stuck open- displaced anteriorly
Soft tissue examination Masseter Primary action? Most likely to cause what problems? Common perpetuating factors
-primary action: elevation of the mandible
-most likely to cause restricted jaw opening
common perpurtuating factors:
-gross trauma
-microtrauma or bruxism
-chronic overwork (chewing)
-poor posture
-significant occlusal imbalance
-holding mandible in other than rest position for long time
If you have sever shortening- unilateral tight masseter, jaw will point to involved side
View slide 16 for location of trigger points
Soft Tissue Exam: Medial pterygoid Primary action can cause what? What happens when the mouth opens if there is tightness on one pterygoid?
Evaluation of the TMJ
What are TP locations in medial pterygoid? 18
Primary action: unilateral-lateral deviation of mandible to contralateral side. Bilaterally elevation of the mandible.
rarely used in isolation, often with lateral pterygoid.
generally causes deviation to the contralateral side and difficulty in late opening.
Soft tissue exam:
Lateral pterygoid:
action?
What may cause problems in this muscle?
TP location and refferal patterns pg 20
Lateral pterygoid:
Action: protrudes and depresses mandible (inferior portion)-opening
Superior part: applies traction to condyle and disc complex during closing.
problems:
-excessive gum chewing
-may develop as satellite TP’s to key TP’s in neck muscles.
-lateral deviation to ipsilateral side in opening or closing
-difficulty closing is more common than opening.
Evaluation of the TMJ
What are the signs and symptoms of TMJ disorders?
Signs:
- History of trauma
- Noise from joint (clicking)
- myofacial pain & tenderness: masseter temporalis
- decreased ROM in opening or lateral deviation
Symptoms:
- pain in TMJ itself, neck pain, facial pain or headaches
- Auricular symptoms: otalgia (ear pain), tinnitis (ringing in ears), hearing loss or a full feeling in the ear.
TMJ disorders can be classified into 3 categories what are they and what structures would be involved in each?
Intra-capsular- degeneration of the disc
Capsula- Synovitis, capsularitis
Extra-capsular- masseter, medial/ lateral pterygoids etc
What would be causes of intracapsular problems
ie disc or meniscitis
- caused by trauma, prolonged muscle spasm or severe occlusion disorders
- late opening click/ early closure click
- crepitus due to meniscal degenration
- may progress to OA of the TMJ
Other:
- OA
- RA
- psoriatic Arthritis
- Gout
What could be some causes of a capsular problem?
-Sprain
-capsulitis
-synovitis
these commonly follow a trauma or as a consequence of intracapsula pathology e.g. RA
What would be some causes of extra capsular TMJ dysfunction?
- disorders of mm’s of mastication
- often pterygoid spasms which cause anterior displacement of the meniscus
Which Pterygoid muscle causes pain on opening/ closing?
Medial pterygoid causes painful restricted movement on opening jaw
Lateral pterygoid- some restriction in opening, but most often in closing, sometimes tinnitus.
what are the things you can do for treatment of TMJ issues?
Whats some advice you can give your patient?
- Requires evaluation of TMJ movements
- effects on TMJ itself, capsule and myofascial structures
- correct upper cervical mechanics
STT
-primary masseter, medial/laterl pterygoid
=temporalis, digastric, supra and infra-hyoid musculature, cervical postural muscles
Advice:
- learning and maintaining good posture
- avoidance of oral habits like exhaustive chewing, clenching and grinding of teeth
- home self stretch exercises
