Orbital Periosteum (Periorbita)

periorbita

The periorbita is the periosteal lining of the bony orbit, continuous with the dura mater at the optic canal and superior orbital fissure. It is loosely attached to the orbital walls except at the orbital rim where it firmly adheres.

Anatomical Data

Boundaries & Contents

Location	Lining of the bony orbit
Boundaries	Lines all four walls of the orbit, loosely attached except at sutures, fissures and the orbital margin Continuous with the dura mater at the optic canal and superior orbital fissure Continuous with the periosteum of the face at the orbital margin, where the orbital septum attaches Gives attachment at the orbital apex to the common tendinous ring
Contents	Orbital fat, extraocular muscles, eyeball, and the orbital vessels and nerves

Biomechanics

Function & Actions

Forms a fibrous envelope around the orbital contents and acts as a barrier that slows the spread of infection, bleeding or tumour between the orbit and the sinuses.

Clinical Relevance

Clinical Notes

Subperiosteal haematoma (from orbital floor blowout fractures or trauma) collects between periorbita and orbital walls, producing proptosis and diplopia. Subperiosteal abscess (from paranasal sinusitis) tracks under the periorbita producing medial proptosis. Orbital decompression for thyroid eye disease involves periorbita incision and fat removal.

Pathology

Common Injuries & Conditions

Subperiosteal Haematoma

Blunt orbital trauma separating the periorbita from the orbital walls producing subperiosteal blood collection, managed conservatively or with drainage for vision-threatening cases.

Subperiosteal Abscess from Sinusitis

Periorbital spread of sinus infection beneath the periorbita producing medial wall proptosis, requiring urgent IV antibiotics and surgical drainage.

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