Imaging and Interventional Procedures for the Lacrimal Duct System

Abstract

To evaluate the lacrimal drainage system using diagnostic imaging, some knowledge of the anatomy of the lacrimal drainage system is required. The relevant structures are shown in Fig. 15.1a. Figure 15.1b presents a similar image of the lacrimal drainage system obtained by digital subtraction dacryocystography. The lacrimal points are located on the edge of the upper and lower eyelids in the medial corner of the eye. They are turned slightly inward and lie adjacent to the eyeball. The puncta form the entrance to the canaliculi. Initially, the upper and lower canaliculus are almost at right angles with the edge of the eyelid, but after some 2mm they curve sharply to run more or less parallel with the edge of the eyelid. The total length of the upper canaliculus is about 10mm, and the lower canaliculus is about 12mm in length (Cowen and Hurwitz 1996). They merge in the medial corner of the eye to form the common canaliculus, also known as the sinus of Maier, which varies in length from 1 mm to several millimeters and ends in the lacrimal sac. The common canaliculus is not perpendicular to the surface of the lacrimal sac, but enters it at an angle of less than 90%. When an obstruction further down in the lacrimal drainage system causes a pathologic swelling of the lacrimal sac, as may happen with a mucocele or pyocele, for instance, this can cause kinking in the common canaliculus, preventing drainage of the lacrimal sac contents via the canaliculi.KeywordsStent PlacementNasolacrimal DuctBony CanalVascular SheathLacrimal DuctThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.