It is oval in form and measures from 12 to 15 mm. in length; its upper end is closed and rounded; its lower is continued into the nasolacrimal duct. Its superficial surface is covered by a fibrous expansion derived from the medial palpebral ligament, and its deep surface is crossed by the lacrimal part of the orbicularis oculi, which is attached to the crest on the lacrimal bone. Histology Like the nasolacrimal duct, the<unk>  is lined by stratified columnar epithelium with mucus-secreting goblet cells, with surrounding connective tissue. The<unk>  also drains the eye of debris and microbes.
Lacrimal sac
Lacrimal groove
Orbital septum
Optic recess
Central canal
Hemotympanum
Ateronon
Syrinx 