Bursa are sacs that are often placed in places where they can rub against, such as bone and soft tissue, tendons, or muscles. arthritic cyst Refers to inflammation of the sac. The trochanter bone is the femur (thigh bone) that forms in the hip joint. hip joint cyst is a disease of the supraclavicular sac of the hip joint It occurs in more women than men, usually between the ages of 40 and 60, but it can happen at any age. not a serious problem But it can be uncomfortable and limited.