Temporomandibular joint dislocation represents the condyle of the mandible being abnormally displaced, with a loss of the normal articulation with the glenoid fossa.
Dislocations of the temporomandibular joint (TMJ) are common and occur in as many as 7% of the entire population, at some point in their lives 3. They can occur at any age but are most common between 20-40 years of age 3.
Dislocations can occur in a number of directions 1:
- anterior dislocation (common)
- cranial dislocation (uncommon)
- posterior dislocation (rare)
Anterior dislocations are most common and represent either an exaggerated and often recurrent (also known as habitual) normal anterior translation of the condyle out of the glenoid fossa and onto the condylar eminence (see TMJ dysfunction), or the result of acute and forceful opening of the mouth (e.g. trauma, intubation 2 etc...) 1,3. In some settings, the dislocation may not be reduced and become chronic.
Cranial dislocations are quite uncommon and are the usually the result of an upward blow to the mandible such that the condyle fractures the glenoid fossa and protrudes into the middle cranial fossa 1.
Posterior dislocations are rare.
- 1. Mel Mupparapu. Oral Radiology: Interpretation and Diagnostic Strategies, An Issue of Dental Clinics of North America,. ISBN: 9780323414487
- 2. Sriganesh K, Farooq S, Byrappa V. Temporomandibular joint dislocation during tracheal intubation in a patient with Sjogren syndrome. Journal of neurosurgical anesthesiology. 27 (1): 82-3. doi:10.1097/ANA.0000000000000097 - Pubmed
- 3. Marqués-Mateo M, Puche-Torres M, Iglesias-Gimilio ME. Temporomandibular chronic dislocation: The long-standing condition. Medicina oral, patologia oral y cirugia bucal. 21 (6): e776-e783. Pubmed