Kemar Green, DO, Department of Neurology, Michigan State University; Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine
This is a 40-year-old man with a right hypertropia that worsened in left and down gaze in addition to right head tilt, and improved in left head tilt. There was subjective excyclotorsion OD with double Maddox rod testing. This was consistent with a right 4th nerve palsy. He had a known left midbrain cavernoma which had bled several years prior to this evaluation making the localization of his 4th nerve palsy "central". Given the proximity of the left 4th nucleus and its fascicle to the left medial longitudinal fasciculus (MLF) and oculosympathetic tract, when a left internuclear ophthalmoplegia (INO) and/or left Horner's syndrome, respectively, is seen with a right (CONTRALATERAL) 4th nerve palsy, a "central" 4th is strongly suggested relating to the decussating course of the 4th nerve (see https://collections.lib.utah.edu/details?id=1260008). However, an isolated 4th nerve palsy can also be central and related to nuclear and/or fascicular injury, as in this case.
Spencer S. Eccles Health Sciences Library, University of Utah