Subtitles in English for this video can be displayed by clicking on  (first button on the bottom right hand corner of the video). The size of the pupillary aperture at any point in time is dependent on a balance between sympathetic tone, parasympathetic tone, the light ...

The patients in these two photos show the classical signs of Horner’s syndrome. In the first photo (Figure 1), there is left-sided partial ptosis, miosis and anhidrosis. Whilst in the second photo (Figure 2), there is right-sided ptosis and miosis. Horner’s syndrome is caused by ...