The lacrimal sac is a small, pouch-like structure located in the inner corner of the eye. It is part of the lacrimal apparatus, which is responsible for the production and drainage of tears. The lacrimal sac collects tears from the eye through the puncta, tiny openings on the eyelids, and channels them into the nasolacrimal duct. When we blink or cry, tears flow over the surface of the eye and are directed into the lacrimal sac. From there, they travel down the nasolacrimal duct and drain into the nasal cavity, which is why our nose may run when we cry.