Raeder described the paratrigeminal syndrome that consists of Horner’s syndrome and sixth nerve palsy.

It is characterized by severe, unilateral facial pain and headache in the distribution of the ophthalmic division of the trigeminal nerve in combination with ipsilateral oculosympathetic palsy or Horner syndrome.

The first patient described by Raeder, in 1918, had an incomplete Horner syndrome with preserved sweating on the side of the lesion. Raeder originally described absent facial anhidrosis in the paratrigeminal syndrome, although the literature suggests no definite consensus concerning the facial sweating pattern. ¹⁾.