Tenon's capsule

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Tenon's capsule
The right eye in sagittal section, showing Tenon's capsule (semidiagrammatic).
Details
LocationOrbit (anatomy)
Identifiers
Latinvagina bulbi, capsula Tenoni
MeSHD058475
Anatomical terminology

Tenon's capsule (

Latin: vagina bulbi) or the fascia bulbi, is a thin membrane which envelops the eyeball from the optic nerve to the corneal limbus
, separating it from the orbital fat and forming a socket in which it moves.

The inner surface of Tenon's capsule is smooth and is separated from the outer surface of the

subarachnoid
cavities and is traversed by delicate bands of connective tissue which extend between the capsule and the sclera.

The capsule is perforated behind by the ciliary vessels and nerves and fuses with the sheath of the optic nerve and with the sclera around the entrance of the optic nerve. In front it adheres to the conjunctiva, and both structures are attached to the ciliary region of the eyeball.

The structure was named after Jacques-René Tenon (1724–1816),[1] a French surgeon and pathologist.

Structure

Relations

Tenon's capsule is perforated by the tendons of the

check ligaments
.

suspensory ligament of the eye. It is slung like a hammock below the eyeball, being expanded in the center, and narrow at its extremities which are attached to the zygomatic and lacrimal bones
respectively.

Clinical significance

Inflammation

Main article: Tenonitis

Tenon's capsule may be affected by a disease called idiopathic orbital inflammation, a condition of unknown etiology that is characterized by inflammation of one or more layers of the eye. The disease is also known as orbital inflammatory pseudotumor, and sometimes may only affect the lacrimal gland or the extraocular muscles.[2]

Local anaesthesia

Local anaesthetic may be instilled into the space between Tenon's capsule and the sclera to provide anaesthesia for eye surgery, principally cataract surgery. After applying local anaesthetic drops to anaesthetise the

retrobulbar
approaches. Akinesia (paralysis of the external eye muscles) may be less complete, however.

References

  1. S2CID 37899713
    .
  2. ISBN 978-1416054542
    .
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