Which statement is true about bursae?

• A. They are synovial-lined sacs that facilitate movement by reducing friction
• B. They are non-synovial
• C. They are primarily rigid structures without fluid
• D. They only occur in the knee

Answer: (A)

Bursae are small fluid-filled sacs lined by a synovial membrane that sit between moving structures to reduce friction. The synovial lining produces lubricating fluid, allowing tendons, muscles, and skin to glide smoothly over bones during movement. Because of this lubrication, bursae are found in many joints, not just the knee—examples include the subacromial bursa of the shoulder and the trochanteric or prepatellar bursae around the hip and knee. They are not non-synovial, they are not rigid and fluid-free, and they are not exclusive to the knee. This friction-reducing, synovial-lined, fluid-filled nature explains their role in facilitating smooth joint motion.