In addition to those already mentioned, examples include temporomandibular joint pain dysfunction syndrome, temporomandibular pain dysfunction syndrome, temporomandibular joint syndrome, temporomandibular dysfunction syndrome, temporomandibular dysfunction, temporomandibular disorder, temporomandibular syndrome, facial arthromyalgia, myofacial pain dysfunction syndrome, craniomandibular dysfunction (CMD), myofacial pain dysfunction, masticatory myalgia, mandibular dysfunction, and Costens syndrome. The lack of standardization in terms is not restricted to medical papers. Notable internationally recognized sources vary in both their preferred term, and their offered definition. For example:

"Temporomandibular Pain and Dysfunction Syndrome – Aching in the muscles of mastication, sometimes with an occasional brief severe pain on chewing, often associated with restricted jaw movement and clicking or popping sounds." (Classification of Chronic Pain, International Association for the Study of Pain). "Headache or facial pain attributed to temporomandibular joint disorder." (International Classification of Headache Disorders 2nd edition (ICHD-2), International Headache Society). "Temporomandibular joint-pain-dysfunction syndrome" listed in turn under "Temporomandibular joint disorders" (International Classification of Diseases 10th revision, World Health Organization). By cause and symptoms
It has been suggested that TMD may develop following physical trauma, particularly whiplash injury, although the evidence for this is not conclusive. This type of TMD is sometimes termed "posttraumatic TMD" (pTMD) to distinguish it from TMD of unknown cause, sometimes termed "idiopathic TMD" (iTMD). Sometimes muscle-related (myogenous) TMD (also termed myogenous TMD, or TMD secondary to myofascial pain and dysfunction) is distinguished from joint-related TMD (also termed arthogenous TMD, or TMD secondary to true articular disease), based upon whether the muscles of mastication or the TMJs themselves are predominantly involved.
Diagnosis
Pain is the most common reason for people with TMD to seek medical advice. Joint noises may require auscultation with a stethoscope to detect. Clicks of the joint may also be palpated, over the joint itself in the preauricular region, or via a finger inserted in the external acoustic meatus, which lies directly behind the TMJ. The differential diagnosis is with degenerative joint disease (e.g. osteoarthritis), rheumatoid arthritis, temporal arteritis, otitis media, parotitis, mandibular osteomyelitis, Eagle syndrome, trigeminal neuralgia, oromandibular dystonia, deafferentation pains, and psychogenic pain. Diagnostic criteria
Various diagnostic systems have been described. Some consider the Research Diagnostic Criteria method the gold standard. Abbreviated to "RDC/TMD", this was first introduced in 1992 by Dworkin and LeResche in an attempt to classify temporomandibular disorders by etiology and apply universal standards for research into TMD. This method involves 2 diagnostic axes, namely axis I, the physical diagnosis, and axis II, the psychologic diagnosis. Axis I contains 3 different groups which can occur in combinations of 2 or all 3 groups, (see table). McNeill 1997 described TMD diagnostic criteria as follows:
Pain in muscles of mastication, the TMJ, or the periauricular area (around the ear), which is usually made worse by manipulation or function. Asymmetric mandibular movement with or without clicking. Limitation of mandibular movements.