Which symptom is associated with an anteriorly displaced disc without reduction?

An anteriorly displaced disc without reduction in the temporomandibular joint (TMJ) typically leads to jaw locking during opening. This symptom occurs because the disc is positioned in front of the condyle and does not return to its normal position when the jaw is opened. As a result, the patient experiences restricted movement, and in many cases, the jaw may lock in a closed position or allow only minimal opening before getting stuck.

This condition is distinct from other symptoms that may be associated with different forms of TMJ dysfunction. For instance, recurring pain during chewing could be related to other dysfunctions or disc displacements with reduction, where the disc can move back into position but still causes discomfort. The lack of symptoms altogether would not align with the mechanical issues presented by an anteriorly displaced disc, as this condition typically manifests with noticeable symptoms, including pain or restricted movement. Non-painful clicking and popping sounds are more indicative of a disc that is able to reduce, where it moves freely in and out of position during jaw movement. Therefore, the locking of the jaw during opening is the characteristic symptom of an anteriorly displaced disc without reduction.