The temporomandibular joint (TMJ) connects the lower jawbone (mandible) to the temporal bones of the skull, functioning as both a hinge and a sliding mechanism. When the alignment or function of the joint or its surrounding muscles is compromised, it is referred to as a temporomandibular disorder (TMD). TMDs frequently produce noticeable sounds during jaw movement, and understanding these sounds is the first step toward addressing the underlying issue.
Describing the Different Auditory Symptoms
The most commonly reported sound is a clicking or popping noise, typically described as a sharp, sudden event. This sound often occurs when the mouth reaches a particular point in its opening or closing arc. A specific pattern known as reciprocal clicking involves one distinct sound during opening and a second, sometimes softer, sound upon closing the jaw. This type of sound is often repeatable and can sometimes be heard by people nearby.
A different, more concerning sound is crepitus, which has a rougher, continuous quality. Crepitus is often described as a grinding, grating, or crunching noise, similar to walking on sand. Unlike the sharp click, this sound suggests continuous friction within the joint, indicating a more advanced physical change. The presence of crepitus can be felt through the skin as a vibration or rough sensation during movements like chewing or talking.
Less common sounds, such as squeaking or rubbing, also indicate joint friction. These noises suggest a general irregularity in the movement of the joint surfaces.
The Mechanical Causes Behind Jaw Sounds
The sharp clicking or popping sound is mechanically generated by the displacement and subsequent repositioning of the articular disc, a small cushion of cartilage between the jawbone and the skull. This condition is formally known as disc displacement with reduction (DDwR). The disc is often displaced forward (anteriorly) when the mouth is closed.
The opening click occurs when the jaw condyle slides forward and “jumps” over the posterior edge of the displaced disc, recapturing it. The closing click happens when the condyle slides back off the disc’s edge as the jaw returns to the closed position. The force of the jawbone slipping onto or off the disc generates the rapid, audible event.
The abrasive crepitus sound is caused by degenerative changes, such as advanced arthritis or a severely perforated disc. When the disc is permanently displaced or degraded, the condyle can rub directly against the bone of the temporal socket. This direct bone-on-bone contact or the rubbing of roughened joint surfaces produces the continuous, gravelly sound characteristic of crepitus.
When Jaw Noises Indicate Clinical Concern
Hearing a clicking or popping sound does not automatically signify a disorder requiring intervention, as joint noises occur in many people who experience no other issues. However, the sounds become clinically significant when accompanied by other symptoms that indicate functional impairment. The presence of pain in the jaw, face, or ear region suggests that the mechanical disruption is causing inflammation or straining surrounding tissues.
Concern should also increase if the jaw’s range of motion becomes limited, or if the jaw temporarily locks. Locking, where the jaw gets stuck open or closed, often happens when the displaced disc ceases to be recaptured by the condyle (disc displacement without reduction). A sudden cessation of a long-standing clicking sound can sometimes precede this locking event.
Another associated symptom is the onset of ear-related issues, such as tinnitus (ringing or buzzing). Due to the close anatomical proximity of the TMJ to the ear canal and shared nerve pathways, jaw dysfunction can impact the auditory system. Individuals who notice that their tinnitus changes in volume or pitch when they move their jaw may have a TMJ-related issue.
Initial Steps for Evaluation and Diagnosis
If jaw sounds are accompanied by pain, stiffness, or functional issues like locking, seek consultation with a healthcare provider specializing in jaw disorders. The diagnostic process begins with a detailed history of symptoms, followed by a physical examination. The clinician will palpate the joint and surrounding muscles for tenderness and listen to the joint sounds while measuring the maximum opening distance. Opening the mouth less than 30 to 35 millimeters is often considered an abnormal range of motion.
Hard Tissue Imaging
If the physical examination suggests an intra-articular problem, imaging may be ordered. X-rays or Cone Beam Computed Tomography (CBCT) are utilized to get detailed views of the hard tissues, which helps evaluate the condition of the bone.
Soft Tissue Imaging
Magnetic Resonance Imaging (MRI) is considered the standard for visualizing the soft tissues of the joint. An MRI can confirm the exact position and morphology of the articular disc, determining if it is displaced and whether joint fluid (effusion) is present. These steps establish the structural and functional status of the joint, guiding the management plan.