ABSTRACT
The Edinger-Westphal nucleus (EW) is a distinct nucleus lying immediately dorsal to the somatic subdivisions of the oculomotor complex. It was first described in a developmental study of human neuroanatomical material by Edinger (1885) and, a short time afterward, in a neuropathological study by Westphal (1887). While both authors recognised this
cytoarchitecturally distinct nucleus located dorsal to the oculomotor nucleus, the study by Westphal additionally led to the suggestion that the EW was involved in the innervation of the iris and possibly other intraocular muscles. This suggestion was made because Westphal studied tissue from an individual who, while alive, had been diagnosed with complete external ophthalmoplegia but whose pupils had constricted for near vision and was thus presumed to have an intact pupillomotor nucleus. Westphal found that the neurons of the large-celled somatic oculomotor nucleus had degenerated, and he correlated this loss with the observed external ophthalmoplegia. However, he found sparing of the neurons of the smaller-celled dorsal nucleus (now known as the EdingerWestphal nucleus), and he correlated these spared neurons with the spared pupillomotor function.
