TMJ

Question 1

The Temporomandibular Joints (TMJ)

Answer 1

The TMJ’s are two of the most frequently used joints in the body

Without these joints, one would be severely hindered when talking, eating, yawning, kissing or sucking

Question 2

Anatomy of the Temporomandibular Joint

Answer 2

• The TMJs are located just anterior to the external auditory meatus (the ear)
• The TMJ is a synovial, condylar, modified ovoid and hinge-type joint with fibrocartilaginous surfaces rather than hyaline cartilage and an articular disc which completely divides each joint into two cavities
• Along with the teeth, these joints are considered to be a “trijoint complex”
• Gliding, translation or sliding movement occurs in the upper cavity of the TMJ, whereas rotation or hinge movement occurs in the lower cavity
• Rotation occurs from the beginning to the midrange of movement through the two condylar heads between the articular disc and the condyle
• The upper head of the lateral pterygoid muscle draws the disc or meniscus anteriorly and prepares for condylar rotation during movement
• Gliding, which occurs as a second movement, is a translatory movement of the condyle and disc along the slope of the articular eminence
• Both gliding and rotation are essential for full opening and closing of the mouth
• The capsule of the TMJs is thin and loose
• The TMJs actively displace only anteriorly and slightly laterally
• With mouth opening, the condyles of the joint rest on the disc in the articular eminences
• As the mandible moves forward on opening, the disc moves medially and posteriorly until the collateral ligaments and lateral pterygoid stop its movement
• The disc is then “seated” on the head of the mandible, and both disc and mandible move forward to full opening
• If the “seating” of the disc does not occur, full ROM at the TMJ is limited
• In the first phase, mainly rotation occurs, primarily in the inferior joint space
• In the second phase, the mandible and disc move together, where mainly translation occurs in the superior joint space
• The TMJs are innervated by branches of the auriculotemporal nerve and masseteric branches of the mandibular nerve
• The disc is innervated along its periphery but is aneural and avascular in its intermediate zone (force-bearing)

Question 3

Ligaments of the Temporomandibular Joint

Answer 3

• The temporomandibular or lateral ligament restrains movement of the lower jaw and prevents compression of the tissues behind the condyle. This ligament is really a thickening in the joint capsule
• The sphenomandibular and stylomandibular ligaments act as “guiding” restraints to keep the condyle, disc and temporal bone firmly opposed
• The stylomandibular ligament is a specialized band of deep cerebral fascia with thickening of the parotid fascia

Question 4

Temporomandibular Joint

Answer 4

• Resting position: Mouth slightly open, lips together, teeth not in contact
• Closed packed position: Teeth tightly clenched
• Capsular pattern: Limitation of mouth opening

Question 5

Patient History

Answer 5

1. Where is the pain? When did it begin? Is the pain constant? How would you rate the pain?
2. Does the client have difficulty swallowing, chewing, eating soft or hard food, yawning?
3. Is there pain or restriction on opening or closing of the mouth?

• Signs and symptoms of TMJ dysfunction include facial pain, ear discomfort, headache and jaw discomfort
• Pain in the fully opened position (yawning) is probably caused by extra-articular problems
• Pain associated with biting firm object (nuts, raw vegetables) is probably caused by an intra-articular problem
• Limited opening may be due to displacement of the disc anteriorly, inert tissue tightness or muscle spasm

4. Is there pain on eating or dynamic loading? Does the client chew on one side or the other?

• Loss of molars or worn dentures can lead to loss of vertical dimension, which can make chewing painful
• dimension is the distance between any two arbitrary points on the face, one of these points being above and the other below the mouth
• Often chewing on one side is the result of malocclusion

5. What movements of the jaw cause pain?

• A history of stiffness on waking with pain on function that disappears as the day goes on suggests OA

7. Does the client breathe through the nose or the mouth?

• Normal breathing is through the nose with the lips closed and no “air gulping”
• If the client is a “mouth breather”, the tongue does not sit in the proper position against the palate

8. Has the client complained of any crepitus or clicking?

• Normally the condyles of the TMJ slide out of the concavity and onto the rim of the disc
• Clicking is the result of abnormal motion of the disc and mandible
• Early clicking implies a developing dysfunction
• Late clicking is more likely to mean a chronic problem
• Clicking may occur when the condyle slides back off the rim into the centre

9. Has the client complained of any crepitus or clicking? continued….

• If the disc sticks or is bunched slightly, opening causes the condyle to move abruptly over the disc and into its normal position, resulting in a single click on opening
• There may be a partial anterior displacement (subluxation) or dislocation of the disc, which the condyle must override to reach its normal position, when the mouth is fully open. This may also cause a click

10. Has the client complained of any crepitus or clicking? continued….

• A click may occur if the disc is displaced anteriorly and/or medially, causing the condyle to override the posterior rim of the disc later than normal during mouth opening
• This may also occur with closing, which is referred to as disc displacement with reduction
• If clicking occurs in both directions it is called reciprocal clicking

11. Has the client complained of any crepitus or clicking? continued….

• Clicks may also be caused by adhesions, especially in people who clench their teeth (bruxism)
• These “adhesive” clicks occur in isolation after the period of clenching
• If adhesions occur in the superior or inferior joint space, translation or rotation will be limited. This presents as a temporary closed lock, which then opens with a click

12. Has the client complained of any crepitus or clicking? continued….

• If the articular eminence is abnormally developed, the maximum anterior movement of the disc may be reached before maximum translation of the condyle has occurred
• As the condyle overrides the disc, a loud crack is heard and the condyle-disc leaps or jogs (subluxes) forward

13. Has the client complained of any crepitus or clicking? continued….

• The “soft” or “popping” clicks that are sometimes heard in normal joints are caused by ligament movement, articular surface separation, or sucking of loose tissue behind the condyle as it moves forward
• These clicks usually result from muscle incoordination

13. Has the client complained of any crepitus or clicking? continued….

• The “hard” or “cracking” clicks are more likely to indicate joint pathology or joint surface defects
• Soft crepitus (like rubbing knuckles together) is a sound that sometimes occurs in symptomless joints and is not necessarily an indication of pathology
• Hard crepitus (like a footstep on gravel) is indicative of arthritic changes in the joints

14. Has the mouth or jaw ever locked?

• Locking may imply that the mouth does not fully open (closed lock) or it does not fully close (open lock) and is often related to problems of the disc or joint degeneration
• Locking is usually preceded by reciprocal clicking
• If the jaw has locked in the closed position, the locking is probably caused by a disc with the condyle being posterior or anteromedial to the disc

15. Has the mouth or jaw ever locked? continued…

• If there is functional dislocation of the disc with reduction, the disc is usually positioned anteromedially and opening is limited

+ The client complains that the jaw “catches” sometimes so the locking occurs only occasionally

16. Has the mouth or jaw ever locked? continued…

• If there is functional anterior dislocation of the disc without reduction, a closed lock occurs

+ This implies there has been anterior and/or medial displacement of the disc so that the disc does not return to its normal position during the entire movement of the condyle

+ Opening is limited and the mandible deviates to the affected side and lateral movement to the uninvolved side is reduced

17. Has the mouth or jaw ever locked? continued…

• If locking occurs in the open position, it is probably caused by subluxation of the joint or possibly by posterior disc displacement
• With an open lock, there are two clicks on opening, when the condyle moves over the posterior rim of the disc and then when it moves over the anterior rim of the disc
• Then there are two clicks on closing

18. Has the mouth or jaw ever locked? Continued…

• If, after the second click occurs on opening, the disc lies posterior to the condyle, it may not allow the condyle to slide back
• If the condyle dislocated outside the fossa, it is a true dislocation with open lock; the client cannot close the mouth and the dislocation must be reduced

19. Does the client have any habits such as smoking, leaning on the chin, chewing gum, biting the nails, pursing lips, continually moving mouth?

• All of these activities place additional stress on the TMJs

20. Does the client grind the teeth or hold them tightly?

• Bruxism is the forced clenching and grinding of the teeth, especially during sleep
• This may lead to facial, jaw or tooth pain or headaches

21. Does there appear to be any related psychosocial problems or stress-related issues?

+ TMJ dysfunction is often accompanied by related psychosocial issues

22. Are any teeth missing? If so, which ones and how many?

• Loss of one or more teeth is called partial edentulism
• Their presence or absence can have an effect on the TMJs and their muscles

23. Are any teeth painful or sensitive?

• Tooth pain may lead to incorrect biting when chewing, which puts abnormal stresses on the TMJs

24. Are there any ear problems such as hearing loss, ringing in the ears, blocking of the ears, earache or dizziness?

• Symptoms such as these may be caused by inner ear, cervical spine, vestibular dysfunction or TMJ problems

25. Does the client have any habitual head postures?
26. Does the client have headaches?

• TMJ problems can refer pain to the head

27. Does the client ever feel dizzy or faint?
28. Has the client ever worn a dental splint or other dental appliance?
29. Has the client ever seen a dentist, such as a periodontist, orthodontist?
30. Does the client have any cervical spine problems?