A pad-like sac or cavity that prevents friction within a joint is known as a?

A bursa is a pad-like sac or cavity found throughout the body, particularly around joints, that serves the purpose of reducing friction between moving structures, such as bones, tendons, and muscles. The bursa contains synovial fluid, which provides lubrication and allows for smooth movement. This is especially important in areas of the body where there is frequent movement, such as the shoulder or knee joints.

In contrast, the other terms refer to different structures in the body: a fossa is a shallow depression in a bone that can serve as an articulation point, a ganglion typically refers to a collection of nerve cell bodies, and a ligament is a tough connective tissue that connects bones to other bones at a joint. Each of these has distinct anatomical functions that differ from the role of a bursa in minimizing friction, thereby highlighting how a bursa is specifically designed to protect joints and facilitate movement.