SUMMARY
Objective. To describe the anatomy of the lacrimal sac in relation to the lateral nasal wall by cadaver dissection, and to measure the distances of surgically important landmarks from relevant structures for safer and more efficient surgery.Method. A total of 12 endoscopic dacryocystorhinostomy (DCR) were performed on both sides (right and left) of 6 fresh-frozen cadavers. The distances of the lacrimal sac to the posterior edge of the uncinate process, the frontal process of the maxilla, the maxillary ostium, the nasal vestibule, the middle turbinate attachment and the inferior turbinate were measured. In addition, the width and length of the lacrimal sac were measured.Results. The mean width and length of the lacrimal sac were 5.6 mm and 11.1 mm, respectively. The lacrimal sac was located at 15.2 mm from the posterior edge of the uncinate process, at 35.5 mm from the nasal vestibule, at 13.5 mm from the maxillary ostium, at 12.2 mm from the frontal process of the maxilla, at 8.7 mm from the middle turbinate attachment, and at 7.3 mm from the inferior turbinate.Conclusion. This study provides additional measurements regarding the lacrimal sac and its relationships with nearby landmarks for use in endoscopic dacryocystorhinostomy. The distances of the lacrimal sac to the nasal vestibule, the uncinate process and the frontal process of the maxilla are not as reliable as the middle turbinate attachment for predicting the anatomic localization of the lacrimal sac during DCR.