plica semilunaris

The plica semilunaris is a small fold of tissue on the inside corner of the eye.

Lemurs also have a third eyelid known as a nictitating membrane, whereas most other primates have a lesser developed plica semilunaris.

In most primate species, a plica semilunaris is present, although fully developed nictitating membranes can be found in lemurs and lorisoid primates.

The plica semilunaris is the thin upper part of the fold of mucous membrane in the supratonsillar fossa that reaches across between the two arches.

Plica Semilunaris (Third Eyelid) You may not know it, but you have a third eyelid.

In humans, the plica semilunaris and its associated muscles are thought to be the vestigial remnants of the nictitating membrane and its muscles.

Often called a third eyelid or haw, it may be referred to in scientific terminology as the plica semilunaris, membrana nictitans or palpebra tertia.

In humans, the plica semilunaris (also known as the semilunar fold) and its associated muscles are homologous to the nictitating membranes seen in some other mammals and other vertebrates.

This is called the plica semilunaris, or the nictitating membrane.