 Utilizing Hopkins' rod optic system, Austrian doctor Walter Messenklinger visualized and recorded the anatomy of the paranasal sinuses and the lateral nasal walls in cadavers.Specifically, Messerklinger focused on mapping out mucociliary routes.In 1978, Messerklinger published the book titled "Endoscopy of the Nose" on his findings, and his proposed methods to utilize nasal endoscopy for diagnosis.