THE RELATIONSHIP BETWEEN TEMPOROMANDIBULAR-JOINT MOBILITY AND PERIPHERAL JOINT MOBILITY RECONSIDERED

The purpose of this paper was to study the relationship between tempor omandibular joint (TMJ) mobility and mobility of joints and to study t he general character of joint mobility in 83 subjects, 55 females and 28 males (mean age 26.7, range 13-46 years). The subjects were recruit ed from the Department of Oral and Maxillofacial Surgery of the Univer sity Hospital of Groningen. All participants had a good general health and did not present anamnestically, clinically or radiographically TM J disorders. Of these subjects, angular displacement of the mandible r elative to the cranium during maximal mouth opening (AMO) was measured . Furthermore, the maximal range of motion of passive digit five hyper extension, passive thumb apposition to the wrist, active elbow and kne e hyperextension, active ankle dorsal flexion and trunk flexion were m easured. All measurements were performed bilaterally, except trunk fle xion. Calculation of product moment correlations (Pearson) revealed a weak relationship between AMO and mobility of right digit five and elb ows for the total group and between AMO and mobility of both digits fi ve and elbows for women. The correlations were never stronger than 0.4 . Multiple regression revealed that only 25.9% of the total variance o f AMO could be explained by mobility of peripheral joints, age and sex . Calculation of product moment correlations between mobility of perip heral joints, trunk flexion and age revealed weak correlations between the different joints, with the exception of paired joints. Principal component analysis revealed a weak general character of joint mobility . It is concluded that mobility or hypermobility of the TMJ cannot be predicted on the basis of mobility or hypermobility of other joints an d that mobility of any peripheral joint cannot be predicted on the bas is of the degree of mobility of other joints.