Neuroanatomy of the Lacrimal Drainage System: What We Know and What We Need to Know

While the microscopic anatomy and histology of the lacrimal drainage system have been well described, the same cannot be said of its neuroanatomy and neurophysiology, which are largely unknown. Earlier studies have delineated several aspects of lacrimal drainage anatomy, including discrepancies between living and cadaveric dimensions, radiologic anatomy, endoscopic anatomy, and ultrastructural features. However, unlike the peripheral nervous system elsewhere in the body, the neural topography and neural mapping of the lacrimal drainage system are poorly understood. The present review aims to elucidate the existing knowledge and point out the existing gaps in the understanding of the neuroanatomy of the lacrimal drainage system and possible future course to bridge those gaps.