Which statement best describes a transition during jaw opening?

Which statement best describes a transition during jaw opening?

• A. Pure rotation
• B. Lateral translation
• C. Transition from rotation to anterior translation
• D. Retraction

Answer: (C)

Jaw opening proceeds in two phases: a hinge-like rotation around the condyles at first, then a forward gliding (anterior translation) of the mandible as the mouth opens wider. The initial rotation is about the condyle within the inferior joint compartment, but as opening continues, the mandible and the articular disc translate forward over the articular eminence in the superior compartment. This transition from rotation to anterior translation explains how the mouth can open beyond purely hinge movement, with the lateral pterygoid helping pull the disc forward to permit the forward glide. Lateral translation would imply side-to-side movement, and retraction is a backward movement, which don’t describe the normal opening path.

Jaw opening proceeds in two phases: a hinge-like rotation around the condyles at first, then a forward gliding (anterior translation) of the mandible as the mouth opens wider. The initial rotation is about the condyle within the inferior joint compartment, but as opening continues, the mandible and the articular disc translate forward over the articular eminence in the superior compartment. This transition from rotation to anterior translation explains how the mouth can open beyond purely hinge movement, with the lateral pterygoid helping pull the disc forward to permit the forward glide. Lateral translation would imply side-to-side movement, and retraction is a backward movement, which don’t describe the normal opening path.