Orbital septum

The orbital septum is a fibrous extension that starts from the periosteum at the edge of the orbit and reaches into the eyelids. It moves down from the superior margin of the orbit into the upper eyelid, where it attaches to the tendon of the levator palpebrae superioris muscle in the upper eyelid. Similarly, from the inferior margin of the orbit, it moves up into the lower eyelid, attaching itself to the lower tarsus, also known as the lower tarsal plate.

When we close our eyes, the orbital septum and the tarsi together cover the entire opening of the orbit. The septum has openings for blood vessels and nerves to pass from the orbit to the face and scalp.