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Clinical Neuroanatomy
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
There are two forms of voluntarily controlled eye movement: Visual pursuit, where a specific target is fixed and followed, using parietal gaze centres closely integrated with the adjacent visual cortexThe ability to select a new target and relocate vision to suit, via frontal gaze centres utilizing direct voluntary pyramidal motor pathway mechanisms. Damage in either of these areas will cause a conjugate gaze palsy, but because the range of movement of both eyes is identically affected, there is no diplopia. At brainstem level, the need to integrate eye movements controlled by three different cranial nerve nuclei widely spaced in the brainstem requires complex and extremely rapidly conducting internuclear pathways. The most critical of these is the medial longitudinal fasciculus. Damage in this pathway causes internuclear ophthalmoplegias, with disconjugate gaze palsies. These will always cause diplopia as the eyes then move independently.
Complete Horizontal Gaze Paresis Due to Medial Pontine Haemorrhage
Published in Neuro-Ophthalmology, 2023
Joan Pei Yun Sim, Jackie Jia Lin Sim, Sameer Saleem, Dennis Cordato
Bilateral horizontal conjugate gaze palsy remains a highly infrequent clinical occurrence due to its underlying neuroanatomy. In our case, this phenomenon can be best explained by a unilateral haemorrhagic inferior medial pontine lesion that had traversed the midline to affect both PPRFs and/or the abducens nuclei. Our case illustrates the intricacies of brain stem neuroanatomy in which complex neurological manifestations in the one patient can be topographically explained.