Sandbox

Dislocation Type	Frequency	Mechanism	Additional Comments	Associated with fracture?	Image
Anterior	Most common	Spontaneously while patient is yawning, "popping" ears, or laughing Risk factors: Prior dislocation Weakness or laxity of capsule Ligamentous injury	Mandibular condyle forced in front of the articular eminence May happen bilaterally or unilaterally	No
Posterior	Rare	Follows a blow to the mandible that may or may not break the condylar neck	Condylar head may prolapse into the external auditory canal	Possible
Lateral	Rare		Often associated with mandibular fracture	Yes
Superior	Rare	Occur from blow to the partially opened mouth	Associated with cerebral contusions, facial nerve palsy, deafness

EX

Superior dislocations occur after being punched below the mandibular ramus as the mouth remains half-open. Since great force occurs in a punch, the angle of the jaw will be forced upward moving towards the condylar head. This can result in a fracture of the glenoid fossa and displacement of the condyle into the middle cranial fossa, potentially injuring the facial and vestibulocochlear nerves and the temporal lobe. Lateral dislocations move the mandibular condyle away from the skull and are likely to happen together with jaw fractures.

Posterior, superior and lateral dislocations are uncommon injuries and usually result from high-energy trauma to the chin. By contrast, anterior dislocations are more often the result of low-energy trauma (e.g. tooth extraction) or secondary to a medical condition that affects the stability of the joint (e.g. seizures, ligamentous laxity, degeneration of joint capsule).