Tenon's capsule

Diagram of the eye, showing Tenon's capsule.

Tenon's capsule, also known as the fascia bulbi, is a thin membrane that envelops the eyeball from the optic nerve to the corneal limbus. It is an important structure in the anatomy of the eye, providing support and facilitating smooth movement of the eyeball within the orbit.

Anatomy

Tenon's capsule is a fibrous sheath that surrounds the posterior part of the eyeball. It is located between the conjunctiva and the sclera, forming a socket in which the eyeball moves. The capsule is continuous with the dura mater of the optic nerve posteriorly and blends with the conjunctival stroma anteriorly.

Structure

The capsule is composed of dense connective tissue and is divided into two layers:

• The outer layer, which is thicker and more fibrous, provides structural support.
• The inner layer, which is thinner and more elastic, allows for the smooth movement of the eyeball.

Function

Tenon's capsule serves several functions:

• It acts as a barrier, protecting the eye from infections and injuries.
• It provides a smooth surface for the movement of the eyeball, reducing friction between the eye and the surrounding tissues.
• It helps maintain the position of the eyeball within the orbit.

Clinical Significance

Tenon's capsule is involved in various surgical procedures, such as strabismus surgery and enucleation. During these procedures, the capsule is often incised or manipulated to access the underlying structures of the eye.

Strabismus Surgery

In strabismus surgery, the muscles attached to the eyeball are adjusted to correct misalignment. Tenon's capsule is carefully dissected to expose the extraocular muscles and allow for their repositioning.

Enucleation

In cases where the eyeball must be removed, such as in severe trauma or ocular tumors, Tenon's capsule is used to create a socket for an ocular prosthesis. This helps maintain the shape of the orbit and provides a base for the prosthetic eye.

Related Pages

• Eye anatomy
• Sclera
• Conjunctiva
• Optic nerve
• Strabismus