orbital septum

(redirected from arcus marginale)

or·bi·tal sep·tum

[TA]
a fibrous membrane attached to the margin of the orbit and extending into the lids, containing the orbital fat and constituting in great part the posterior fascia of the orbicularis oculi muscle.
Synonym(s): septum orbitale [TA]

orbital septum

A fibrous sheet extending partially across the anterior opening of the orbit within the eyelids.
See also: septum

orbital septum 

A thin membrane containing collagenous and elastic fibres which is attached to the orbital margin at a thickening called the arcus marginale. It is continuous with the tarsal plates of the upper and lower eyelids except where it is pierced by the fibres of the levator palpebrae superioris muscle in the upper lid and the expansion from the inferior rectus in the lower lid. Syn. palpebral fascia; septum orbitale. See dermatochalasis; eyelids; tarsus.