The anatomy of the lacrimal bone at the lateral wall of the nose: its significance to the lacrimal surgeon.

The position, dimension and thickness of the exposed lacrimal bone at the lateral nasal wall in 10 cadaveric half-heads were examined. In all cases, the lacrimal bone at the lateral nasal wall was found to be just anterior to the mid-third of the uncinate process. The average length and width was 7.4 mm and 2.5 mm, respectively. In nine of the 10 half-heads, the lacrimal bone was very thin with an average thickness of 57 mm. In all the cases, the position of the lacrimal passage covered by the lacrimal bone corresponded to the postero-medial aspect of the upper lacrimal duct and the lower lacrimal sac. This study shows that the uncinate process is a reliable landmark for the lacrimal bone in endoscopic nasal surgery. The paper-thin lacrimal bone allows a bone rongeur to infracture through and nibble away the bony covering of the lacrimal sac in a dacryocystorhinostomy.