Cervical Musculoskeletal Impairments and Temporomandibular Disorders

OBJECTIVES The study of cervical muscles and their significance in the development and perpetuation of Temporomandibular Disorders has not been elucidated. Thus this project was designed to investigate the association between cervical musculoskeletal impairments and Temporomandibular Disorders. MATERIAL AND METHODS A sample of 154 subjects participated in this study. All subjects underwent a series of physical tests and electromyographic assessment (i.e. head and neck posture, maximal cervical muscle strength, cervical flexor and extensor muscles endurance, and cervical flexor muscle performance) to determine cervical musculoskeletal impairments. RESULTS A strong relationship between neck disability and jaw disability was found (r = 0.82). Craniocervical posture was statistically different between patients with myogenous Temporomandibular Disorders (TMD) and healthy subjects. However, the difference was too small (3.3º) to be considered clinically relevant. Maximal cervical flexor muscle strength was not statistically or clinically different between patients with TMD and healthy subjects. No statistically significant differences were found in electromyographic activity of the sternocleidomastoid or the anterior scalene muscles in patients with TMD when compared to healthy subjects while executing the craniocervical flexion test (P = 0.07). However, clinically important effect sizes (0.42 - 0.82) were found. Subjects with TMD presented with reduced cervical flexor as well as extensor muscle endurance while performing the flexor and extensor muscle endurance tests when compared to healthy individuals. CONCLUSIONS Subjects with Temporomandibular Disorders presented with impairments of the cervical flexors and extensors muscles. These results could help guide clinicians in the assessment and prescription of more effective interventions for individuals with Temporomandibular Disorders.