Orbital septum

In anatomy, the orbital septum (palpebral fascia) is a membranous sheet that acts as the anterior (frontal) boundary of the orbit. It extends from the orbital rims to the eyelids. It forms the fibrous portion of the eyelids.[1]

Orbital septum
The right eye in sagittal section, with structures of the orbital septum within blue markings.
Details
Identifiers
LatinSeptum orbitale
TA98A15.2.07.003
TA2471
FMA59328
Anatomical terminology

Structure

In the upper eyelid, the orbital septum blends with the tendon of the levator palpebrae superioris, and in the lower eyelid with the tarsal plate.[2]

When the eyes are closed, the whole orbital opening is covered by the septum and tarsi. 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.[3]

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

Clinical significance

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

The orbital septum is an important landmark in distinguishing between orbital cellulitis (inside the septum) and periorbital cellulitis (outside the septum).[4]

Imaging

Orbital septum appears as hypointense on both MRI T1 and T2 weighted images, in contrast with surrounding hyperintense fat.[5]

References

This article incorporates text in the public domain from page 1026 of the 20th edition of Gray's Anatomy (1918)

  1. Mafee MF, Valvassori GE, Becker M (10 November 2004). Imaging of the head and neck. Thieme. pp. 200–. ISBN 978-1-58890-009-8. Retrieved 16 June 2010.
  2. Meyer DR, Linberg JV, Wobig JL, McCormick SA (1991). "Anatomy of the orbital septum and associated eyelid connective tissues. Implications for ptosis surgery". Ophthalmic Plastic and Reconstructive Surgery. 7 (2): 104–13. doi:10.1097/00002341-199106000-00004. PMID 1863562. S2CID 31394816.
  3. Davson H (2008). "Eye, human". Encyclopædia Britannica.
  4. Harrington JN. Ing EB (ed.). "Cellulitis, Orbital: eMedicine Ophthalmology". MedScape. Retrieved 16 June 2010.
  5. Ferreira TA, Pinheiro CF, Saraiva P, Jaarsma-Coes MG, Van Duinen SG, Genders SW, et al. (March 2020). "MR and CT Imaging of the Normal Eyelid and its Application in Eyelid Tumors". Cancers. 12 (3): 658. doi:10.3390/cancers12030658. PMC 7139934. PMID 32178233.

Further reading
  • Brémond-Gignac DS, Deplus S, Cussenot O, Lassau JP (1994). "Anatomic study of the orbital septum (22.10.93)". Surgical and Radiologic Anatomy. 16 (1): 121–4. doi:10.1007/BF01627937. PMID 8047962. S2CID 11745470.

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