Myalgia, Myofascial Pain, Arthralgia, and Headache: The Different Kinds of TMD Pain

By Dr. Boris Zusin · Published September 30, 2026

When patients describe “TMJ pain,” they're often describing one of several genuinely distinct conditions, not a single diagnosis. The validated diagnostic framework used in TMD care (DC/TMD) separates jaw and face pain into a handful of specific categories — muscle pain (myalgia and myofascial pain), joint pain (arthralgia), and headache attributed to TMD are the ones with the strongest diagnostic evidence behind them. Telling these apart matters clinically, because the source of the pain, not just its location, is part of what determines the right treatment. This page walks through how each is actually defined.

Myalgia: Pain Localized to the Muscle

Myalgia refers to pain felt in a chewing muscle without pointing to any more specific mechanism — it's simply pain in the muscle itself. Clinically, it's identified by two things: a complaint of pain localized to a particular area, and pain that gets measurably worse with provocation. That provocation can be tested either by applying pressure to the skin overlying the muscle (palpation) or by having the muscle work against resistance, such as testing how far the jaw can move in a given direction. If pressing on a specific spot in the jaw muscle reproduces the pain you've been feeling right there, that's the hallmark of myalgia.

Myofascial Pain: When It Spreads or Refers Elsewhere

Myofascial pain is also muscle pain, and in practice the term is often used almost interchangeably with myalgia — the distinction between the two may have limited clinical significance for how either is actually managed. What sets myofascial pain apart, when it is distinguished, is one of two patterns: spreading pain (pain that extends beyond the initial point pressed) or pain referral (pain that shows up in a completely different location — often the temple, ear, or neck — remote from where the muscle was actually pressed). This referral pattern is a big part of why TMD-related muscle pain can masquerade as a headache, earache, or neck problem: the muscle generating the pain and the place you feel it aren't always the same spot.

Arthralgia: Pain That Comes From the Joint Itself

Arthralgia is the joint's counterpart to myalgia — pain localized to the temporomandibular joint itself, identified using the same basic approach: a specific complaint of joint pain, made worse by palpating the joint directly or by testing jaw movement. In theory, it might seem useful to further pin down exactly which structure inside the joint is generating the pain. In practice, the TMJ is simply too small for that level of anatomic precision to be reliable or clinically useful based on the current evidence, so arthralgia is diagnosed as joint pain in general rather than assigned to one specific internal structure. The same general treatment principles that apply to myalgia apply here too — though arthralgia can also show up alongside a TMJ disc disorder or degenerative joint disease (osteoarthritis), which is why a joint exam looks for both pain and mechanical findings like clicking, locking, or crepitus together, not pain in isolation. See our TMJ Appliances page for how disc disorders and degenerative joint disease are evaluated and treated.

Headache Attributed to TMD

The fourth category with validated diagnostic criteria is headache secondary to a painful TMD. Whether this is best thought of as a headache disorder or a TMD is almost beside the point clinically — headache and TMD pain overlap and share underlying pathophysiological mechanisms, clinical characteristics, and neurovascular anatomy, which is exactly why this comorbidity has its own specific name and diagnostic criteria rather than being left to guesswork. The headache itself can be of any type (migraine, tension-type, or otherwise); what makes the diagnosis is that a painful TMD must also be present, and — critically — the headache pain must actually be reproduced by the same clinical provocation techniques used to identify myalgia or arthralgia (pressing on the jaw muscles or joint, or testing jaw movement). The point of pinning this down isn't academic: if a headache is genuinely secondary to a painful TMD, treating the TMD may be all that's needed, without a separate headache-specific treatment plan. The reverse can happen too. Because odontogenic and TMD-related head pain can closely mimic migraine and other primary headaches, this is an area where a careful history matters; see our post on whether a toothache can cause a headache for a fuller look at that differential.

Disc Disorders (Internal Derangement)

Separate from the pain diagnoses above, disc displacement — the articular disc losing its normal functional relationship with the jaw's condyle — is a mechanical joint finding rather than a pain diagnosis in its own right. It's genuinely common: an estimated one-third of adults have disc displacement in at least one TMJ, and for most of them it causes little to no functional impact and no pain at all. Other TMD problems can coexist with a symptom-free disc, but a painless, displaced disc by itself generally doesn't need treatment. For a smaller subset of people, disc displacement is associated with real pain, limited opening, and disability — and what separates the two groups isn't well understood. The cause of disc displacement itself is largely unknown; growth mismatches between the condyle and the developing bite have been suspected but aren't well supported by the evidence, and trauma (including whiplash) has been proposed but the research behind that link is limited by weak study designs.

In the milder form, the disc returns to its normal position as the jaw opens (with a popping or clicking sound sometimes marking that return, or the reverse displacement on closing) — this is diagnosed with MRI. In the more severe form, the disc stays displaced through the full range of opening; in the acute phase this can mechanically block normal opening, while in the more chronic phase the tissue behind the disc stretches out and mobility often returns, sometimes with the tissue itself remodeling into a functional "pseudo-disc" that lets most people regain normal jaw function and motion even without the original disc back in a textbook position. An important clinical point: none of these disc displacement patterns can be reliably diagnosed just from clicking sounds or watching the jaw deviate during opening. MRI remains the actual diagnostic standard, and it's reserved for cases involving significant mechanical problems, suspicion of more serious disease, or situations where treatment hasn't worked and an exact diagnosis will actually change the plan — not for every click. See our anterior repositioning splint post for how a clicking, displaced disc is actually managed when treatment is warranted.

Degenerative Joint Disease (Osteoarthritis vs. Osteoarthrosis)

Breakdown of the bone in the TMJ condyle goes by several names — osteoarthritis, osteoarthrosis, and degenerative joint disease all describe the same underlying bony change. Within TMJ research specifically (unlike general medical literature, where the two terms are often used interchangeably), osteoarthritis denotes degenerative change with pain present, while osteoarthrosis denotes the identical structural change without pain — a distinction that matters because asymptomatic, adaptive bony change in this particular joint is common. Degenerative joint disease develops from chronic abnormal mechanical loading on the joint, and it can follow a long-standing, advanced disc displacement — though only around 15% of people with disc displacement actually progress to it. When degeneration does cause pain and dysfunction, it can eventually require surgical treatment (arthrocentesis, arthroscopy, open joint surgery, or total joint replacement) if conservative care doesn't resolve it. One point worth internalizing from research in other load-bearing joints like the knee: how much pain and disability someone experiences from degenerative joint disease isn't well predicted by how much bony destruction shows up on a scan — it's better explained by the same broad biopsychosocial factors that apply to TMD generally. Two joints that look identical on imaging can behave very differently in the same patient.

TMJ Subluxation and Luxation (Dislocation)

The jaw joint's condyle has a normal, expected range of motion. In some people, the condyle moves beyond that range and gets momentarily stuck — called subluxation — or gets stuck in a more extreme position that requires someone to manually guide it back into place, called luxation or dislocation. (The literature isn't fully consistent in how these two terms are defined and used.) This is typically distressing and often painful when it happens, though in some people this same degree of extreme joint movement doesn't lead to a stuck, dislocated jaw at all. The suspected contributors include the angle of the bony ridge that bounds the front of the joint space (thought to play a role in recurrent dislocation, though the evidence is largely observational), recurrent wide yawning, or an external injury to the jaw — though for most people who experience it, no clear cause is ever identified. Recurrent dislocation is generally thought to reflect a stretched joint capsule and ligaments (a form of joint instability), and treatment approaches range from joint-stability exercises to injections meant to encourage connective-tissue tightening in the capsule, to surgical correction of the bony shape in more severe, recurrent cases — though the underlying mechanisms behind why these help aren't fully understood.

Two Broad Categories: Painful Disorders vs. Mechanical Joint Disorders

Stepping back, the common TMDs actually split into two genuinely different kinds of problems. Myalgia, myofascial pain, and arthralgia are painful disorders that behave like musculoskeletal pain conditions found elsewhere in the body, and they're treated using the same general principles — they're even formally classified as part of the broader International Classification of Orofacial Pain alongside neuropathic and visceral facial pain. Disc displacement, degenerative joint disease, and subluxation/luxation, by contrast, are mechanical joint disorders that can cause pain but don't require pain as part of their diagnosis — which is exactly why they don't fit neatly into an orofacial-pain framework and are better understood as primarily orthopedic joint problems, similar in spirit to a mechanical knee or shoulder condition. Both categories, though, benefit from being assessed within the same biopsychosocial framework: research in other joints makes clear that psychological and behavioral factors shape how much pain and disability a mechanical joint problem actually produces, not just the structural finding itself.

Why the Distinction Actually Matters

Muscle pain, joint pain, headache attributed to TMD, and mechanical joint findings like disc displacement or degenerative change aren't managed identically, even though the same appliance-based and behavioral treatments often help more than one of them at once. A muscle-dominant presentation points toward muscle-focused therapy (jaw relaxation, physical therapy, a stabilization splint), a joint-dominant presentation raises the question of disc position or degenerative change and may call for MRI or CBCT imaging, and a headache-dominant presentation needs the provocation criteria confirmed before it's treated as TMD-related rather than a separate headache disorder. In practice, patients frequently have more than one of these categories at once — which is exactly why a proper TMD evaluation maps out where and how your specific pain and joint findings behave, rather than treating “jaw pain” as a single undifferentiated complaint. See our TMJ Appliances page for how this fits into a full evaluation and our original diagram of how the common TMDs are classified.