TMJ (Jaw)
TMJ Dislocation (Open Lock)
턱관절 탈구 (열린 잠김)
Condyle displaces anterior to articular eminence, preventing mouth closure
- How common
- Uncommon (emergency)
- Typical age
- All ages
What is it?
During wide opening (yawn, dental procedure), condyle translates anterior to eminence; muscle spasm prevents spontaneous reduction.
Commonly affected: Unilateral or bilateral condyles (bilateral more common)
How it develops
- Excessive OpeningWide yawn or dental procedure
- Anterior TranslationCondyle translates beyond articular eminence
- Muscle SpasmLateral pterygoid/temporalis spasm blocks return
- Open LockCannot close mouth
Symptoms
- Inability to close mouthMouth stuck open
- Severe joint painExcruciating preauricular pain
- Speech difficultyCannot articulate clearly
- DroolingCannot control saliva
- Preauricular depressionEmpty fossa palpable before ear
How it is examined
- Mouth fixed openCannot close jaw
- Empty glenoid fossaPalpable empty fossa with condyle anteriorly
- Protruded mandibleJaw protrudes forward
- Muscle spasm/tendernessTemporalis/masseter spasm, tenderness
Imaging
Panoramic/CT confirms dislocation and excludes fracture (pre/post reduction).
- Condyle anterior to eminence
- Empty glenoid fossa
- Exclude associated fracture
Not routine in emergency; used for recurrent cases.
- Ligamentous laxity in recurrent cases
- Possible disc changes
- Not for acute diagnosis
Non-surgical care
- Manual reduction (Hippocratic)Thumbs on lower molars, press down and back to reduce
- Sedation/muscle relaxantMidazolam/diazepam if reduction difficult
- Local anesthesiaLateral pterygoid block relaxes spasm
- Post-reduction careBarrel bandage, soft diet, avoid wide opening 1–2 weeks
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Recurrent/chronic (>3 episodes or failed manual reduction)
Procedures that may be discussed
- Eminoplasty (augmentation)
- Eminectomy
- Capsular plication
Outlook
Most resolve with manual reduction; surgery for recurrent cases.