Abstract
To test the validity of the hypothesis that irritation of the cervical sympathetic nerves is a cause of hyper-tonicity of the cervical soft supporting tissues, especially the deep nuchal muscles, and that this hypertonicity is a cause of traumatic vertigo of cervical origin, we examined 44 vertigo cases with whiplash injury by testing equilibrium function and EMG discharges from the neck before and after administration of drugs affecting the sympathetic receptors. The results obtained were as follows: