Sesamoid bone

Definition

A sesamoid bone is a small, round bone that is embedded within a tendon, where the tendon passes over a joint. These bones serve to protect the tendon and increase its mechanical advantage by modifying pressure, reducing friction, and altering the direction of muscle forces.

Related terms

Tendon: A flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone.

Joint: A structure in the body where two parts of the skeleton are fitted together, allowing for movement or support.

Patella: Also known as the kneecap, it is the most well-known example of a sesamoid bone that improves leverage for knee extension