Lacrimal Apparatus - Structure of the Eye

Lacrimal Apparatus

The lacrimal gland (B19) lies above the lateral angle of the eye; it is divided by the tendon of the levator muscle of the upper eyelid into an orbital part (B20) and a palpebralpart (B21). Its excretory ducts at the con-junctival fornix secrete the lacrimal fluid (tears), which keeps the anterior aspect of the eyeball continuously moist and collects in the lacrimal lake of the medial angle of the eye. Here at the inner surface of each eyelid is a small opening, the lacrimal point (B22), which leads to the lacrimalcanaliculus(B23). The canaliculi ascend anddescend, respectively, and then turn at a right angle to join and open into the lacrimalsac (tear sac) (B24), from where thena-solacrimal duct (tear duct) (B25) leads to theinferior meatus of the nose. Blinking not only results in uniform moistening of the eyeball surface but also has a sucking effect on the flow of tears by expanding and con-stricting the nasolacrimal duct.