Cervical spine alignment and hyoid bone positioning with temporomandibular disorders.

The relationships between temporomandibular joint (TMJ) disorders and cervical structure dysfunctions have already been demonstrated. The aim of the present study was to investigate functional and structural alterations of the head and neck of 17 individuals with TMJ disorders (TMD group), compared with a control group of 17 asymptomatic subjects in a cross-sectional design. The outcome variables included pain on palpation of the sternocleidomastoideus, superior trapezius and subocciptal muscles, as well as radiographic measures of alignment of the cervical spine and positioning of the hyoid bone. Cervical alignment, determined by measures of the cervical curvature angle, was investigated by the Cobb method. Independent Student t-tests were used to investigate differences between groups for all outcome variables (alpha < 0.05). The results demonstrated that individuals with TMJ disorders, when compared with asymptomatic subjects, presented higher levels of perception of pain in all cervical muscles (P < 0.0001). No significant differences were found between groups for the cervical alignment measures. In the TMD group, the position of the hyoid bone in relation to the cervical spine did not appear to be different from the control group.