A patient with temporomandibular joint pain has a kyphotic, forward head posture. This posture MOST likely results in which mandibular change?

• A. Anterior displacement of the mandible
• B. Posterior displacement of the mandible
• C. Lateral displacement of the mandible
• D. Posterior displacement of the maxilla

Answer: (B)

Posture of the head and neck directly changes how the jaw sits in the TMJ. When the head is forward and the upper body is kyphotic, the line of gravity shifts anteriorly, and the mandible tends to rest in a more retruded, or posterior, position relative to the maxilla. This back-buzzed position places the condyles higher and more posterior in the glenoid fossae and increases load on the retrodiscal tissues, which can contribute to TMJ pain. Muscles of mastication adjust to hold the teeth in contact in this retruded position, reinforcing the tendency for a posterior displacement of the mandible. An anterior displacement would occur with forward protrusion of the jaw, while lateral displacement would show a side-to-side shift, and a posterior displacement of the maxilla isn’t a typical consequence of this posture.