Deep cervical flexor muscle dysfunction in whiplash

Objective: To measure the deep neck flexor muscle function for its contribution to cervical segmental stabilization. Methods: A staged test of deep neck flexor action, cranio-cervical flexion, was devised. Activity in the superficial neck flexors [electromyography] and the change in shape of the cervical curve, aligned to deep flexor contraction [pressure sensor] was measured, in whiplash subjects and asymptomatic controls. Results: Whiplash subjects used more activity in superficial muscles in the test and were less able to control pressure changes than controls. Conclusion: The test appears to detect poorer motor control in the neck flexors in whiplash subjects, the increased co-activation of the superficial neck flexors being a likely compensation for reduced deep neck flexor function.