The nasolacrimal drainage apparatus is the escape route for tears and consists of three parts:
1. The puncta: There are four, with one each at the inside corner of each eyelid, just on the inside of the lid margins.
2. The lacrimal sacs: There are two, one for each eye. These are dilated or widened areas that connect the two ducts that extend from each punctum. Dacryocystitis is the term used for inflammation of the lacrimal sacs.
3. The nasolacrimal ducts (tear ducts): There are two and each extends from each lacrimal sac and continues along the muzzle under the lining of the roof of the nose.

Disorders of the nasolacrimal drainage apparatus include congenital deformities (birth defects), infections, foreign bodies such as plant awns or seeds, and tumors. The disorders may occur on just one or on both sides.

General anesthesia may be required for effective treatment. The patient’s activity must be curtailed during the healing period.