SOMATOTOPIC ORGANIZATION OF THE CRANIAL NERVE NUCLEI INVOLVED IN EYE MOVEMENTS: III, IV, VI.

The oculomotor nucleus is divided into: 1. somatic medial column innervating the superior rectus muscle and somatic lateral column, further subdivided into a lateral column innervating the inferior rectus, inferior oblique and medial rectus muscles; 2. central nucleus innervating the levator palpebrae superioris muscle; 3. visceral nucleus innervating the pupillary sphincter muscle, consisting of the following two groups of neurons: cholinergic, preganglionic neurons supplying the ciliary ganglion, termed the Edinger- Westphal preganglionic (EWpg) neuron population, and the centrally projecting, peptidergic neurons, termed the Edinger-Westphal centrally projecting (EWcp) population. A detailed understanding of the position of both nuclei and their subgroups supplying the individual muscles is an essential prerequisite for eye movement assessment, offering a simple clinical method for diagnosing eventual dysfunctions of eye movement generation pathways.