Which instruction best tests TMJ protrusion?

Which instruction best tests TMJ protrusion?

• A. Stick out your lower jaw
• B. Open your mouth as wide as you can
• C. Move your jaw to the right
• D. Close your mouth gently while biting down

Answer: (A)

Testing forward movement of the mandible. To assess protrusion, ask the patient to stick out the lower jaw. This action moves the mandible forward, translating the condyle and the articular disc along the articular eminence. A smooth, symmetric forward glide with little or no pain suggests normal TMJ function; pain, crepitus, or asymmetry can indicate anterior disc displacement or other joint issues. This movement specifically evaluates the ability of the jaw to protrude and the harmony between the disc and condyle, unlike opening the mouth wide (which tests vertical opening), moving the jaw to the side (which tests lateral excursion), or closing and biting (which tests occlusion and bite force).

Testing forward movement of the mandible. To assess protrusion, ask the patient to stick out the lower jaw. This action moves the mandible forward, translating the condyle and the articular disc along the articular eminence. A smooth, symmetric forward glide with little or no pain suggests normal TMJ function; pain, crepitus, or asymmetry can indicate anterior disc displacement or other joint issues. This movement specifically evaluates the ability of the jaw to protrude and the harmony between the disc and condyle, unlike opening the mouth wide (which tests vertical opening), moving the jaw to the side (which tests lateral excursion), or closing and biting (which tests occlusion and bite force).