Tendon sheath

A tendon sheath is a layer of synovial membrane/synovium that surrounds and protects the tendon. It is a tube-like structure that allows the tendon to stretch and not adhere to the surrounding tissues.

Etymology

The term "tendon sheath" is derived from the Latin word "tendo", which means "to stretch", and the Old English word "sceath", which means "a covering".

Structure

Tendon sheaths are made up of two layers: the fibrous layer and the synovial layer. The fibrous layer is the outer layer and is made up of dense irregular connective tissue. The synovial layer, also known as the inner layer, is a thin layer of cells that produce synovial fluid. This fluid lubricates the tendon and reduces friction, allowing the tendon to move freely.

Function

The primary function of the tendon sheath is to reduce friction between the tendon and the surrounding tissues. This is achieved by the production of synovial fluid by the synovial layer of the sheath. The fluid lubricates the tendon, allowing it to move smoothly and efficiently.

Clinical Significance

Inflammation of the tendon sheath, known as tenosynovitis, can cause pain and limit the movement of the affected tendon. This condition can be caused by injury, overuse, or infection. Treatment typically involves rest, physical therapy, and in some cases, surgery.

Related Terms

• Tendon: A flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone.
• Synovial Membrane: A type of connective tissue that lines the inner surface of capsules of synovial joints and tendon sheath.
• Tenosynovitis: The inflammation of the fluid-filled sheath (the synovium) that surrounds a tendon.

See Also

• Tendonitis
• Synovial Joint
• Connective Tissue