The Crossed Flexor Plantar Response in Patients with Klippel-Feil Syndrome.

The plantar reflex is one of most important and widely tested components of the neurological examination. We describe 3 subjects with Klippel-Feil syndrome and mirror movements where unilateral cutaneous stimulation of the foot leads to flexor plantar responses in both feet. We discuss the evidence which suggests that this "crossed flexor" plantar response reveals a transcortical pathway for the flexor plantar response.