|Dislocation of the Mandible /
Jaw Dislocation / TMJ Subluxation
Predisposing Factors for Jaw Dislocation:
- Most dislocations occur spontaneously on opening
the mouth widely for yawn, dental work, during an
- Trauma may also produce dislocation
- Trauma involving a downward force on partially
- Those with previous dislocations are at much greater
risk for repeat dislocation
- Shallow mandibular fossa may predispose to
- Connective tissue diseases like Marfan’s or Ehlers-
Danlos may have increased risk
- May eventually result in osteoarthritis in TM joint
- Dislocations of the lower jaw (mandible) tend to be uncomfortable but not
severely painful for the patient
- The presence of a jaw fracture increases the pain
- Patients are unable to close mouth completely
- Difficulty speaking and, possibly, swallowing
- Dislocations may be one-sided or both (unilateral or bilateral)
- The lower jaw comes forward (pro-gnathic) appearance to jaw when both are
|Last Updated 2nd May 2016
Once radiographs have been obtained that confirm a dislocation and exclude a
mandibular fracture, reduction attempts may proceed. Patients with mandibular
fractures should be referred to the OMFS Department. Uncomplicated
dislocations can be managed in the A&E ± LA ± conscious sedation.
If the dislocation has just happened, no sedation or LA is needed. The longer the
patient has been dislocated, the more likely either LA ± sedation or in more severe
Relocation: An initial attempt can be made for the patient to self-relocate by
eliciting the gag-reflex. Stimulation of the soft palate can induce the patient to
gag. This can spontaneously re-locate the subluxed mandible.
Gauze pads should be wrapped around both thumbs to prevent human bite injuries
as the mandible is reduced. The thumbs are placed on the lower molars (or over
the retro-molar pads) and the inferior surface of the mandible is grasped with the
fingers on each side. Downward pressure is exerted on the lower molars to free
the condyle from its entrapped position in front of the articular eminence.
Following this, the mandible is eased backwards to return it to its anatomic
position. Successful reduction is usually evident as the teeth will close rapidly due
to masseter spasm and a palpable (and sometimes audible) clunk occurs on
reduction. The clinician must beware of having their thumbs being trapped in an
inadvertent human bite as the mandible relocates.
Dislocation of the mandible / jaw dislocation / TMJ
subluxation is an infrequent A&E presentation.
The condition is discomforting to the patient, although
most are not in severe pain. In the majority of cases, the
mandible (lower jaw) can be reduced by the A&E staff
using simple techniques. Rarely, a mandibular dislocation
may require open reduction under general anæsthesia.
Once the condyle (see below diagram) comes out of its
fossa, it comes to lie in front of the articular eminence
and is mechanically blocked from spontaneously moving
back into its correct position (in the fossa).
Spasm of the masseter and pterygoid muscles (chewing
muscles) results in trismus (limited mouth opening) and
further traps the condyle in its dislocated position. The
resulting dislocation may be one sided or both. In either
case, the patient will be unable to completely close the
mouth and will often have difficulty speaking.
The dislocation is surprisingly not very painful unless an
associated mandibular fracture is present.
- Conventional X-ray is usually diagnostic
- Mandibular condyle lies forward (anterior) to the articulate eminence on one
or both sides
|Barton Bandage to reduce
the chance of further TMJ
Further Inpatient Care:
In the rare cases of mandible dislocation that cannot be reduced by the method
described above, attempted closed reduction under GA or open reduction may be
required. Similarly, chronic dislocations or fractures / dislocations of the mandible
are best reduced by OMFS or ENT specialists.
Further Outpatient Care:
Successfully relocated mandibular dislocations do not require any specific
ongoing treatment, although the patient should be cautioned against wide opening
of the mouth, which could easily cause a recurrence.
All patients with reduced mandibular dislocations should be followed-up by an
appropriate specialist because of the possibility of jaw instability, ligamentous
damage and chronic TMJ pain.
Serious complications from mandibular dislocation are rare. There are several
complications that are associated with the dislocation and reduction.
Fracture of the mandibular condyle can occur during dislocation. Open fractures
are at risk for infection and osteomyelitis. Interposition of soft tissues may make
the dislocation irreducible.
Injury to the external carotid artery and facial nerve have been reported.
Complications of Reduction:
The clinician accomplishing the reduction may sustain a human bite as the jaw
closes rapidly on reduction.
The mandibular condyle may fracture as it passes under the articular eminence.
Because the dislocation occurs in anatomically predisposed individuals and
disrupts the joint capsule and ligaments that stabilise the TMJ, recurrent
dislocation is very common.
Recurrent dislocation often results in osteo-arthritis of the TMJ with chronic pain
There are many surgical interventions to correct chronic dislocation and painful
TMJ syndrome that are described in the ENT literature. Because so many of the
patients with mandible dislocation experience recurrent dislocation, it is advisable
to refer all of these patients to an appropriate specialist for follow-up.
Patients should be instructed to avoid opening their mouths widely to prevent
Confirmation of relocation: Repeat radiographs are indicated to confirm reduction
and exclude the possibility of fracture during reduction.
The patient should be observed for airway patency and if sedation has been used,
vital signs monitored until the effects of the sedatives have worn off.
The patient should be cautioned to avoid wide opening of the mouth to prevent
recurrent dislocation. A Barton's bandage is applied to prevent wide mouth opening
and recurrent dislocation.
|Relocation of the subluxed TMJ - note,
gauze wrapped around the thumbs