Topography of the nasolacrimal duct on the lateral nasal wall in Koreans

The aim of this study was to describe in detail the gross anatomy of the nasolacrimal apparatus in relation to the lateral nasal wall by the various steps of cadaver dissection and to measure the distances of surgically important landmarks from relevant structures to improve the safety and efficiency of endoscopic surgical procedures. Thirty-six half-heads of embalmed Korean adult cadavers were dissected under a surgical microscope. After removal of the nasal septum, the lateral wall of the nasal cavity was examined. The orifice of the nasolacrimal duct (NLD) was most frequently observed in the form of a vertical sulcus in 14 cases (39%) and the lacrimal fold was present in 28 cases (77.8%). A total of 15 morphometric items between the orifice of the NLD and the adjacent anatomical structures were measured. The location of the orifice of the NLD was observed at a mean of 17.5 +/- A 3.1 mm from the limen nasi, 22.8 +/- A 4.8 mm from the anterior nasal spine, and 21.4 +/- A 3.5 mm from the axilla of the middle nasal concha. In the positional relationships, the most frequent finding was that the lacrimal sac was posterior to the axilla of the middle nasal concha in 23 cases (64%), and overlap of the NLD with the maxillary line was observed in 24 cases (67%). This study was conducted to accumulate anatomic data on the lacrimal sac and duct with regard to the positional relationships among the surrounding structures to establish the information for use in endoscopic dacryocystorhinostomy.