Orbital septum

In the upper eyelid it blends with the tendon of the Levator palpebræ superioris, and in the lower eyelid with the tarsal plate.

In some sources, the orbital septum refers to this sheet (here called the palpebral fascia) along with the tarsal plate.

When the eye is closed, the whole orbital opening is covered by the septum. Medially it is thin, and, becoming separated from the medial palpebral ligament, attaches to the lacrimal bone at its posterior crest. The medial ligament and its much weaker lateral counterpart, attached to the septum and orbit, keep the lids stable as the eye moves.

The septum is perforated by the vessels and nerves which pass from the orbital cavity to the face and scalp.

With age the septum may weaken, and as a result orbital fat may herniate forwards. The operation to correct this is called blepharoplasty.

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