Clinical features

Horner's syndrome comprises:

• ipsilateral miosis and partial ptosis
• ipsilateral anhidria on the face
• there is no enopthalmos, although the narrow palpebral aperture may suggest it

Also:

• despite the ptosis - normal range of lid movement in and up and down movement - supplied by the third nerve
• despite the miosis, the pupillary response to light and the near reflex are brisk and sustained but dilation of the Horner's pupil in response to darkness is diminished or absent
• the degree of miosis is not related to the level of the lesion i.e. whether central, pre- or post- ganglionic