The significance of a crossed extensor hallucis response in neurologic disorders: a comparison with the Babinski sign.

The significance of a crossed extensor hallucis response on active flexion of the hip was analysed in various neurological disorders. It is concluded that this sign, not formerly described, is a pathological reflex or synkinesia. In the cooperative patient the crossed extensor response is a more sensitive indicator of a minor disturbance within the cortico-spinal motor pathways than the Babinski sign. With lesions above the foramen magnum a crossed extensor hallucis response is observed more frequently than the Babinski sign.