[Horner's syndrome. With special reference to topographical diagnosis].

The triad miosis, ptosis and hemifacial anhidrosis make up the well-known Horner's syndrome. This is caused by a lesion or a dysfunction in the "oculosympathetic pathway" running from the hypothalamus to the eye. Various disease entities may manifest themselves in this way, and it is important to be able to determine whether the dysfunction is localized to the central, preganglionic or postganglionic neurone. This review presents the various tests used for this purpose, describes our recent contributions in the field, and finally proposes a simple scheme that is suitable for topographical diagnosis.