Bursas are small sacs filled with fluid, located in various parts of the body, that help to reduce friction between bones, tendons, muscles, and other tissues. There are several synonyms for bursas, including bursae, synovial bursas, fluid-filled sacs, and synovial sacs. These structures play an important role in maintaining joint health and mobility. When bursas become inflamed or irritated, the condition is known as bursitis, which can cause pain and stiffness in the affected area. Treatment for bursitis may include medication, physical therapy, ice or heat therapy, or in severe cases, surgery.