Dissectional and endoscopical anatomy of the lacrimal duct

Abstract

Abstract Purpose: A better knowledge of the external and internal anatomy of the lacrimal duct isessential for any intervention. The induced prussure of the medial canthal ligament into the lacrimal sac might be considered as one of the reasons of epiphora. Methods: In this study, cadaver disection, trans‐canalicular and endonasol endoscopy are used to provide a better intuition of anatomy. Results: Concerning the medial canthal ligament, cadaver study of the lacrimal duct reveals that there are two portions: the posterior portion and anterior one which passes over the lacrimal sac and inserts on the lacrimal bone. The medial portion of the medial canthal ligament is connected by the medial part of the tarsus superior and inferior. There are fascial connections between the anterior part of the ligament and the lacrimal sac and between the anterior part of this ligament to the orbicular superior and inferior muscels.The lacrimal duct starts from the Punctum superius and inferius and terminates in the nose. The inferior opening of the duct comes in the nose on the level of the inferior turbinate.Collaps of the canaliculi or the lacrimal sac is investigated by trans‐canalicular endoscopy. It is observed that the pressure induced by medial canthal ligament into the lacrimal sac is the main reason of collps of the canaliculi or the lacrimal sac. Conclusions: Trans‐canalicular and endonasal endoscopy which are complementary to disectional anatomy, provid a better insight of the naso‐lacrimal duct anatomy and physiology. This knowledge is mandatory for any naso‐lacrimal duct interventions. Epiphora with exclusion of the other ethiology (allergy, foreign body) than obstruction, can be caused by collaps of the lacrimal sac due to pressure of the medial canthal ligament.