What is a sac of synovial fluid near a joint commonly referred to as?

A sac of synovial fluid located near a joint is commonly referred to as a bursa. A bursa serves as a cushion and reduces friction between tissues such as bone, tendons, and muscles during movement. This anatomical structure is particularly important in areas where there is a lot of movement, as it allows for smooth motion and prevents inflammation and damage to the surrounding tissues.

In contrast, the term synovial cavity refers to the space within a synovial joint that contains synovial fluid, but it is not the same as a bursa. A tendon sheath is a specialized structure that surrounds tendons, providing a protective covering and reducing friction as tendons slide over bony structures. A ligament, on the other hand, is a connective tissue that connects bone to bone, providing stability to joints but does not have the same cushioning effect as a bursa. Understanding the distinction between these structures is crucial for comprehending joint anatomy and function.