Three-dimensional characteristics of neck movements in subjects with mechanical neck disorder

Study design: Controlled laboratory study. Objectives: To examine characteristics of neck movement at three-dimensional planes for subjects with mechanical neck disorder (MND) and measure cervical range of motion, coupling motion, and calculation of the upper cervical rotation ratio. Background: MND ischaracterized bysymptomsof neck pain, headache, dizziness andlimitedrangeof motion(ROM).However, the characteristics of neck movements across the three-dimensional planes in MND patients remain unknown. Methods: Forty participants were recruited, which consisted of twenty-seven subjects with MND and 13 healthy subjects. A three-dimensional electromagnetic motion capture device with custom data analysis software was used to measure the neutral position of the neck and the range of motion of upper and lower cervical spine. Results: The results indicate that subjects with MND had significantly decreased ROM in right rotation ( p< 0.05) and extension ( p< 0.05) movements compared to the healthy group. Increased coupling motion ( p< 0.05) in the rotation plane during cervical flexion was also found in the MND group compared to control group. For rotations in neutral or in flexion positions, rotation to the right showed smaller range of motion compared to rotation to the left. Conclusion: In this study, MND was associated with altered cervical movement patterns with increases in coupling motion. The findings may help to differentiate MND from whiplash-associated disorder. Increasing upper cervical spine rotation mobility may be crucial for treating deficiencies in neck rotation in patients with MND.