The authors begin by enumerating the various syndromes in which painful ophthalmoplegia may be observed (sphenoidal fissure syndrome, Collier's syndrome, syndromes involving the orbital apex, the cavernous sinus and parasellar syndromes; Raeder's syndrome, Gradenigo's syndrome and Fischer-Brugge syndrome). They then discuss the various causes that must be investigated in all cases of painful ophtalmoplegia. They consider in order: -- ophtalmoplegia due to general causes (especially diabetes) and neurological causes (e.g. multiple sclerosis); -- ophtalmoplegia due to common local canses space-occupying processes, vascular malformations, ear, nose and larynx infections); -- painful ophalmoplegia of unknown origin, which includes four entities of very differing importance (Gubler and Charcot's ophthalmoplegic migraine and Tolosa-Hunt syndrome of which the clinical symptoms and course are so different that they can be distinguished as two entities; and, secondarily, inflammatory pseudo-tumours of the orbit and the recurrent multiple cranial nerve palsies that are observed in South-East Asia). (Acta nurol. belg., 1977, 77, 331-350).