TMJ (Jaw)
TMJ Disc Displacement with Reduction
턱관절 원판전위 (가역성)
Disc displaces then reduces during opening, producing a click
- How common
- Common (~30% of population)
- Typical age
- Ages 20–40
What is it?
Disc displaces anteriorly at rest; during opening, condyle slides under disc and reduces with a click.
Commonly affected: Anterior or anteromedial disc displacement
How it develops
- Disc Attachment LaxityPosterior attachment stretches
- Anterior DisplacementDisc sits anterior to condyle at rest
- Reduction on OpeningCondyle slips under disc → opening click
- Reciprocal ClickDisc redisplaces on closing → reciprocal click
Symptoms
- Opening clickAudible 'pop' on opening
- Reciprocal clickClick on both opening and closing
- Mild TMJ painIntermittent periarticular pain
- Deflection on openingS-shaped opening path (unilateral displacement)
- Normal opening rangeOpening >40 mm (differentiates from closed lock)
How it is examined
- Palpable/audible clickClick palpable/audible on open-close
- Normal max openingMax opening >40 mm
- Opening deviationDeflects before click, then returns to midline
- Mild joint tendernessMild lateral pole tenderness
Imaging
Panoramic/transcranial view usually normal; assess bone.
- Normal bony structures
- Normal joint space
- Excludes other pathology
MRI is gold standard — closed/open mouth T1/PD shows disc position.
- Anterior disc at closed mouth
- Disc reduces on opening
- Normal or mildly deformed disc
- Possible effusion
Non-surgical care
- Education/reassurancePainless clicking usually needs no treatment
- Soft diet/jaw restAvoid wide opening and gum chewing
- NSAIDsShort-term use if painful
- Splint + PTStabilization splint and jaw exercises
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Conservative failure with significant pain/dysfunction
Procedures that may be discussed
- Arthroscopy with lysis/lavage
- Disc repositioning (discopexy) — rare
Outlook
Painless clicks often observed; painful cases respond to conservative care.