The lacrimal apparatus is the system for tear production and drainage. Tears contribute to the tear film covering the eye and is critical for providing nourishment to the cornea, providing a medium for oxygen to diffuse through, washing out foreign material and as a source of antibacterial enzymes.

Tears are produced in the lacrimal gland, found in the the lacrimal fossa, a depression at the superolateral part of the orbit. Its main part is about the size and shape of an almond, with a small palpebral part extending into the upper eyelid. The gland is drained by a series of 8-14 ducts opening into the lateral part of the superior conjunctival fornix.

Tears are washed over the eye by blinking and pool into the lacrimal lake formed by the lower conjunctival cul-de-sac. This pool drains through small openings, the lacrimal puncta, on the medial margin of each eyelid. These puncta continue as canaliculi and open into the lacrimal sac, located on the medial surface of the orbit, formed by the lacrimal bone and frontal process of the maxilla. This, in turn, drains through the nasolacrimal duct into the anterior part of the inferior nasal meatus. This opening is guarded by a fold of mucous membrane which prevents air from being forced up the duct into the sac when blowing one’s nose.