What is the initial cause of mandibular dislocation?

The initial cause of mandibular dislocation is typically excessive opening of the mouth followed by rapid closure. This mechanism causes the head of the mandible to slip out of its normal position in the glenoid fossa of the temporal bone, leading to dislocation.

When the mouth opens excessively, the articular disc can move anteriorly and eventually get stuck in a way that prevents the mandible from returning to its proper place. Rapid closure can exacerbate the situation, forcing the jaw to become displaced and resulting in a dislocated jaw.

Understanding that this specific action can lead directly to dislocation helps highlight the importance of being cautious during dental procedures and while yawning or laughing, which can lead to similar movements. The other potential causes, while they may contribute to the risk of dislocation in some contexts or represent complications after dislocation, do not initiate it as directly as the mechanism of excessive opening followed by rapid closure does.