What prevents the TMJ disc from becoming compromised in a normally functioning joint?

The correct choice highlights the important structures that help maintain the integrity of the TMJ disc during normal joint function. The retrodiscal tissue, along with the superior and inferior laminae, plays a crucial role in stabilizing the disc. This tissue acts as a cushioning mechanism and facilitates the movement of the disc with respect to the condyle and the glenoid fossa during movements like opening and closing the mouth.

Additionally, the ligaments associated with the TMJ, such as the temporomandibular ligament, help maintain the appropriate position of the disc relative to the mandible and ensure that it can function without becoming displaced or compromised. Together, these components work cohesively to provide both support and flexibility, allowing for smooth movements and preventing injury to the disc.

Other choices do not encompass the same range of protective and supportive structures necessary for the proper functioning and stabilization of the TMJ disc. Relying solely on synovial fluid would not provide the structural support needed; while the articulating surfaces of the bones may assist in joint function, they do not prevent disc damage. Similarly, the muscles of facial expression are not directly involved in protecting or stabilizing the TMJ disc, as their primary role is in facial movement rather