Developmental anatomy of nasolacrimal duct.

Abstract

As A PART of the scientific exhibit of the American Academy of Ophthalmology and Otolaryngology, in 1950, I reviewed the developmental anatomy of the nasolacrimal duct. At that time, and since, I have been repeatedly asked for reprints of, or references to, the literature on this subject. Although much of the material used in the exhibit has been published in the anatomic, embryologic, and ophthalmologic literature, some of it is original, and the remainder bears repetition. The nasolacrimal passageway arises from a thickening of the ectoderm in the naso-optic fissure. The thickened ectoderm buries itself in the mesenchyme between the lateral nasal process and the maxillary process, detaches itself from the surface, and extends downward. Later, the epithelial cord canalizes and becomes patent at the ocular end and, finally, at its lower nasal end. The latter, the nasal connection, may often not be completed at birth. In the 7-mm., or