The part of the eyelid that opens to expose the eyeball is called the lacrimal fissure, and the part near the nose is called the medial canthus. There are two main structures in the medial canthus: the first one is a small aperture that can be seen in each of the upper and lower eyelids near the medial canthus, and these two apertures are called tear ducts, which are the channels for the tears to flow out of the eyes, and through the tear ducts the tears go into the nasolacrimal ducts, and then into the nasal cavity, which is a very important part of the tear circulation. This is a very important part of the tear circulation. Secondly, a round or oval bulge can be observed in the inner canthus, which is called the lacrimal caruncle, and it protects the tear duct and nearby parts of the tear duct from irritants when the eyes are open. When blinking or closing the eyes, the tear caruncle squeezes the tear fluid further into the tear ducts, thus promoting tear circulation.