Lacrimal apparatus

The system that produces and drains tears. The lacrimal apparatus of the eye includes the main and accessory lacrimal glands and the nasolacrimal drainage duct. The main gland lies just within the upper and outer margin of the eye orbit and drains on to the conjunctiva. It secretes tears during crying and when the eye is irritated. The accessory gland lies within the conjunctiva, and maintains the normal tear film, secreting it directly onto the conjunctiva. Tears drain through the lacrimal puncta, tiny openings towards the inner ends of the upper and lower eyelids. The puncta are connected by narrow tubes to the lacrimal sac, which lies within the lacrimal bone on the side of the nose. Leading from the sac is the nasolacrimal duct, which opens inside the nose.


Online Medical Dictionary: Your essential reference to over 5000 medical terms.