Anatomy

The capsule of the joint contains a thick and fibrous layer that is above and thin layers lie deep. Along with the capsule, the ligaments improve the knee stability. Ligaments provide more stability when in extended position than in flexed position. The synovial membrane is inside the capsule, which provides the nourishment to the surrounding structure. It also releases synovial fluid, which lubricates the knee joint. The infrapatellar fat pad and bursa provide shock absorbing to the knee from the external forces. In the semi-flexed position, the synovial fluid is under the least stress and is the most beneficial position in case of joint effusion.