Tenon capsule

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The Tenon capsule, also known as fascia bulbi or bulbar sheath, functions as an extraocular muscle pulley. It also provides a socket which separates the globe from the surrounding fat and allows free movement. It merges posteriorly with the dural sheath of the optic nerve and extends anteriorly to the limbus. There is a potential space between the Tenon capsule and sclera called the "sub-Tenon space," "episcleral space," or "peri-scleral lymph space," which is used in anesthetizing the globe.

Tenon capsule is composed of anterior and posterior parts:

  • the anterior, or muscular, part is a thick fibrous tissue containing collagen, elastin and smooth muscles
  • the posterior part is merely condensed collagen fibers

History and etymology

It is named after the French surgeon and pathologist JR Tenon, who described it in 1805.