The most common disorders affecting the jaw are temporomandibular joint (TMJ) disorders and jaw dislocation. TMJ disorders include conditions that cause myalgias, arthralgia, headaches, and biomechanical dysfunction in and around the TMJ. They commonly affect young adults and are likely multifactorial in origin. The diagnosis is clinical and based on characteristic features, which include pain, headache, limitations in jaw functioning, and clicking or grinding of the TMJ. Most patients are treated conservatively, e.g., with oral analgesics, behavior modification, heat therapy, and/or splints, and those with refractory symptoms are referred to a specialist. TMJ dislocation can occur unilaterally or bilaterally as a result of extreme mouth opening or direct trauma. Patients present with an inability to close their mouths, impaired speech, and visible facial deformities. The standard treatment is closed reduction. Complications include mandibular fractures, neurovascular injuries, dental injuries, and repeat dislocations. Irreducible TMJ dislocations and mandibular fracture-dislocations usually require specialized treatment (e.g., surgery).
- Epidemiology: commonly affects young adults (prevalence 15–31%; peak age 20–40 years) 
- Behavioral factors: e.g., poor head and/or cervical spine posture, possibly bruxism 
- Psychological factors: e.g., depression, anxiety, stress
- Trauma to the TMJ: e.g., cervical spine or jaw injuries
- Abnormal processing of trigeminal nerve pain: e.g., sensitization
- Substance use disorder: e.g., cocaine, MDMA, methamphetamines 
Clinical features 
- Aggravating factors
- Other symptoms
Consider a more serious cause of trismus (e.g., head and neck cancer, deep neck infection, tetanus, acute dystonic reaction) if trismus is sustained, progressive, severe, occurs without jaw clicking, or accompanied by atypical symptoms, e.g., lymphadenopathy or oral lesions. 
- TMJ disorders are .
- Diagnostic criteria for temporomandibular disorders (DC/TMD) are used clinically and for research. 
- Multiple TMD subtypes exist with unique individual criteria.
- Generally, a TMD is diagnosed if characteristic clinical features (e.g., pain, locking, clicking, headache):
- Imaging (e.g., CT, MRI) is typically used to rule out other diagnoses (e.g., fracture, infection) and if symptoms persist despite conservative treatment.
- Begin a trial of conservative management for all patients.
- If there is no improvement in 2–4 weeks or a severe acute exacerbation, consider imaging, outpatient specialist consultation, and treatment escalation as needed. 
- General measures
- NSAIDs (e.g., naproxen): first-line agents (see “Oral analgesics” for dosages) 
- Muscle relaxants (e.g., cyclobenzaprine): generally added for patients with evidence of a muscular component (e.g., muscle spasms, tenderness to palpation) 
- Inadequate improvement after 2–4 weeks of conservative treatment, NSAIDs, and/or muscle relaxants: Consider adding tricyclic antidepressants (e.g., amitriptyline), benzodiazepines (e.g., diazepam), or anticonvulsants (e.g., gabapentin). 
- Intraarticular corticosteroid injection
- Other injectable agents: intraarticular hyaluronic injections, botulinum toxin injections
- Surgery (rarely required)
- Significant and/or prolonged mouth opening (e.g., yawning, dental procedures, acute dystonic reaction)
- Direct trauma
- Anatomic predisposition
- Weakness or injury to the TMJ ligaments
Anterior TMJ dislocation (most common): The mandibular condyle becomes trapped anterior to the mandibular fossa (can occur unilaterally or bilaterally).
- With wide mouth opening, the articular surface of the mandibular condyle rotates and glides anteriorly.
- If the condyle slides past the articular eminence of the mandibular fossa, spasm of the pulls it superiorly, locking it in place.
- Dislocations in other directions (e.g., posterior, lateral) are rare.
Clinical features 
- Inability to close the mouth
- Impaired speech
- Palpable and/or visible depression in the preauricular space
- Unilateral dislocation: deviation of the jaw to the contralateral side
TMJ dislocation is typically a .
- Atraumatic: Routine imaging is unnecessary.
- Traumatic: Obtain imaging to rule out a fracture, e.g., CT face (see “Diagnostics” in “Mandibular fractures”).
- Initial management: Attempt if there are no contraindications.
- Aftercare 
- Disposition 
Consult OMFS if there is a mandibular fracture-dislocation.
- Bite block (optional)
- Digit protection: e.g., tongue depressors, finger splints (optional)
Landmarks and positioning 
- Sit the patient upright with support for the back and head.
- Face the patient or stand behind them, with the elbows at the level of the patient's mandible or higher.
- Administer PSA). (
- Consider inserting a for provider protection.
- With the hands in position, apply steady caudal pressure to the mandible.
- Guide each mandibular condyle inferiorly and posteriorly into the mandibular fossa.
- Evaluate mandibular range of motion after the reduction.
If using the intraoral approach, be careful not to injure the thumbs, as the teeth may snap together at the time of reduction. 
For bilateral TMJ dislocations, it is typically easier to reduce one mandibular condyle at a time rather than both simultaneously. 
Pitfalls and troubleshooting 
- Unsuccessful reduction
- Digital injuries: may be sustained by the provider if an intraoral approach is used