[Anatomical consideration for the injury of dacryocyst and nasolacrimal duct during intranasal sinus surgery].

Based on dissection and measurement on 20 adult head cadavers, there is the close relationship between lacrimal duct and lateral wall of the nasal cavity. The cells of anterior ethmoid sinus were classified into three degrees, according to the relationship between the anterior ethmoid sinus and the lacrimal sac fossa. The average distance is 6.74 +/- 1.72 mm between the nasolacrimal duct and the upper part of the uncinate process, 3.44 +/- 0.75 mm and 5.50 +/- 3.73 mm from the nasolacrimal duct to ethmoidal infundibulum and the maxillary ostium. The orifice of the duct most commonly opens under the insertion of the inferior turbinate anteriorly. To perform intranasal sinus surgery, the safest area and key operation approach were discussed.