Horizontal orientation of the bony lacrimal passage: an anatomical study

To examine the horizontal orientation of the bony lacrimal passage.

The orbits and bony nasolacrimal canals (BNLCs) from 28 Japanese cadavers (11 men and 17 women; average age at death, 83.6 years; range, 70-99 years) were fixed and exenterated before use. After exposing the posterior halves of the lacrimal fossa (LF) and the BNLC, the authors measured the angles of the longitudinal axes of the LF and the BNLC relative to the sagittal line. Based on these values, the relative horizontal orientation of the LF and the BNLC was determined (ΔBNLC-LF). Positive angles of LF and BNLC were defined when the LF and BNLC were directed laterally against the sagittal line. A positive ΔBNLC-LF was defined as having a greater angle for the LF than for the BNLC.

The mean LF and BNLC angles, and the ΔBNLC-LF were 11.9°, 0.1°, and 11.8°, respectively. The LF inclined laterally against the sagittal plane for all sides and the BNLC ran almost parallel to sagittal plane on average. The BNLC inclined inward against the sagittal line (0° or negative BNLC angle) for 28 sides (50.0%) and inclined outward (positive BNLC angle) for 28 sides (50.0%). The angle of the LF in women was statistically greater than that in men, though no gender BNLC angle or ΔBNLC-LF differences were determined.

The horizontal angle of the bony lacrimal passage differs among individuals, with an equal split between medial and lateral inclinations of the BNLC with reference to the sagittal line.