We draw the following conclusions from clinical observations on traumatized patients with vertigo and lumbar pain. 1) Hypertonicity of the lumbar soft supporting tissues, and especially the lumbar erector muscles (i.e., over-excitment of the lumbar proprioceptors) is a cause of vertigo due to whiplash injury. Equilibrium tests after fixing the waist with a corset are useful for detecting ataxia of lumbar origin. 2) Over-excitement of the lumbar porpiroceptors and dysfunction of the brain stem and the cerebellum are closely related in bringing about vertigo due to whiplash injury. The lumbar proprioceptors in particular may be important, in close correlation with the cerebellum in producing vertigo of this type. 3) Infiltration of procaine into tender spots in the lumbar soft supporting tissues is helpful in therapy of disequilibrium of the eyes and body and of cerebellar ataxia.