Morphology and morphometry of lacrimal drainage system in relation to bony landmarks in Caucasian adults: a cadaveric study.

PURPOSE: The objective of this study is to examine the morphometry of the lacrimal drainage system with reference to bony landmarks in the vicinity.

METHODS: Twenty midsaggitalized heads obtained from sixteen preserved cadavers were studied. Measurements involved detailed morphometry of anterior and posterior lacrimal crests, bony lacrimal sac fossa, entrance and length of the bony nasolacrimal duct (NLD), attachment of Horner's muscle, and characteristics of the inferior meatal opening of the NLD.

RESULTS: The mean lengths of anterior and posterior lacrimal crests were 16.3 and 12.5 mm, respectively. At the midpoint of the posterior lacrimal crest, Horner's muscle was found to be attached at a mean of 1.3 mm posterior to the crest. The mean dimensions of the bony lacrimal sac fossa at superior, mid and inferior levels were 6.5, 8.7, and 5.9 mm, respectively. The mean contribution of the lacrimal bone to the lacrimal sac fossa was 56.2%. The mean anteroposterior and transverse diameters of the entrance of the bony NLD were 5.7 and 4.7 mm, respectively. The most common type of NLD opening in the inferior meatus was that of "vertical sulcus" (70%, 14/20). The mean distance of the NLD opening from the anterior nasal spine and Limen nasi were 22.2 and 18.9 mm, respectively.

CONCLUSION: This study provides useful anatomical and positional relationship of bony lacrimal landmarks and nasolacrimal duct in Caucasian adults.