Glossary of TMJ Diagnosis Terms

ANKYLOSIS- Restricted mandibular movement with deflection to the affected side on opening.

  • FIBROUS ANKYLOSIS- Produced by adhesions, usually not painful, limited range of motion opening, deflection to the affected side, limited lateral excursion to the opposite side, and no radiographic findings except absence of condylar translation on opening on the affected side.
  • BONY ANKYLOSIS- The union of the mandible to the articular fossa creating complete immobility of the joint. No pain is present. Limited movement on opening and on excursion to the contralateral side, deflection to the affected side and radiographic evidence of bone proliferation are present.

CAPSULITIS/SYNOVITIS- Inflammation of the capsular ligament, usually appearing clinically as tenderness when the lateral pole of the condyle is palpated. The pain is present even in rest position, but joint movement usually increases the pain. Inflammation of the synovial tissues (synovitis) and the capsular ligament (capsulitis) appear as one disorder clinically. The only way to differentiate is by arthroscopy.

DEVIATION IN FORM- Irregularities of intracapsular soft and hard articular tissue. Usually not painful with repetitive, nonvariable joint noise (if present) occurring at the same point on opening and closing.

DISK DISPLACEMENT WITH REDUCTION- Alteration, usually abrupt, of the disc-condyle structure relationship during mandibular translation. This is usually associated with reciprocal clicking. Reproducible joint noise at different positions during opening and closing. Soft tissue imaging may reveal disc reduction on opening.

DISC DISPLACEMENT WITHOUT REDUCTION- Altered disc-condyle structural relationship that is maintained during translation (acute or chronic). Soft tissue imaging may reveal absence of reduction.

  • ACUTE- Usually extreme pain, limited opening, absence of joint noise, deflection to the affected side on opening, and limited lateral excursion to the opposite side.
  • CHRONIC- Usually little or no pain, history of joint noise and/or limited opening, absence of joint noise other than possible crepitus and limited opening and lateral excursion to the opposite side (slight).

HYPERMOBILITY- Excessive disc and/or condylar translation usually well beyond the eminence. This is usually not painful and soft tissue imaging is usually negative.

HYPERPLASIA- Overdevelopment of the mandible, mandibular condyle, or cranial bones, that is congenital or acquired. A non-neoplastic increase in the number of normal cells. It can occur locally as in the condyle or coronoid or in the entire mandible or side of the face.

HYPOPLASIA- Incomplete or underdevelopment of the mandible, mandibular condyle or cranial bones that is congenital or acquired. Condylar hypoplasia can be associated with fibrous ankylosis.

MANDIBULAR DISLOCATION- The condyle is positioned anterior to the articular eminence and/or disk and unable to return to the closed position. Previously termed subluxation. A true dislocation cannot be reduced by the patient and a subluxation can be reduced by the patient usually in a brief period.

MUSCLE CONTRACTURE- Chronic resistance of a muscle to passive stretch, as a result of fibrosis. This is usually not painful but is associated with limited range of mandibular motion, not caused by joint disorder, and also has unyielding firmness on passive stretch.

MUSCLE SPASM- A sudden, involuntary muscle contraction. Acute pain, marked by limited range of motion, fasciculation, and increased EMG activity even resting may be present. There is acute onset of pain at rest as well as with function.

MYALGIA (LOCAL) – Unclassified- This includes muscle pain secondary to ischemia, bruxism, fatigue, metabolic alterations, delayed onset muscle soreness, autonomic effects, and protective splinting. There are few reliable clinical characteristics that can be used to distinguish them from each other.

MYOFASCIAL PAIN- A regional aching pain associated with localized tenderness in firm bands of muscle and tendons (trigger points). Usually continuous dull pain in one or more muscles and may have reproducible alteration of pain complaints with palpation of specific tender areas termed "active" trigger points.

MYOSITIS- A painful generalized inflammation usually of the entire muscle and can occur in tendinous muscle attachments also. There is usually acute pain and tenderness over the entire muscle with possible swelling and limitation of range of motion. This may be associated with trauma or infection of the muscle.

NEOPLASM- New, abnormal, uncontrolled growth of the cranial bones or mandible. The tumors are usually benign in the TM joints.

OSTEOARTHRITIS- A degenerative condition accompanied by secondary inflammation. Point tenderness on palpation, pain, crepitus, limited range of motion and radiographic evidence of structural bony change.

OSTEOARTHROSIS- A chronic degenerative non-inflammatory condition of the joint characterized by structural changes of the joint surfaces. There is no pain present, or tenderness to palpation, but usually crepitus and radiographic evidence of structural bony changes are present.

POLYARTHRITIDES- Arthritis caused by generalized systemic arthritic condition, including rheumatoid arthritis, juvenile rheumatoid arthritis (Still's disease), spondyloarthropathies, gout, hyperuricemia, and Reiter's syndrome. This group is best diagnosed with serologic tests. Pain, tenderness, crepitus, radiographic structural bony change, limited range of motion and anterior open bite may be present.

REFLEX SPLINTING- Reflex rigidity in a muscle as a means of avoiding pain during movement. Pain, tenderness on palpation, limited range of motion, and rigidity upon mandibular manipulation.

SPRAIN- A traumatic joint injury in which one or more ligaments are stretched, twisted, or avulsed by temporary dislocation or wrenching of the joint. Edema and bleeding occur with hematoma formation.

TRIGEMINAL NEURALGIA- A painful condition that affects the face unilaterally in a distribution of one or more divisions of the trigeminal nerve. Brief shock-like, lancinating pain that is typically precipitated by non-painful stimuli characterizes the pain. It can occur without an obvious stimulus. The pain is usually brief and severe (less than seconds or less). The pain does not cross to the opposite side of the face, but 3 – 5 percent of patients may have this condition affect the face bilaterally.