Vertical wrinkling of the forehead or Procerus sign in Progressive Supranuclear Palsy.

'Procerus sign' has been described as vertical wrinkles in the glabella region and bridge of the nose of patients with Progressive Supranuclear Palsy. The action of Corrugator and Orbicularis Oculi produce the vertical wrinkling. The relevance of this sign in early clinical diagnosis has been established and this sign has gained importance in literature and has been quoted as a useful sign in texts following the original description.