Behind knee pain (also known as posterior knee pain) is one of the most common forms. tendons, muscles, cartilage and ligaments (the ACL, PCL, LCL and MCL).. Swelling behind the knee; A lump behind the knee; Fluid around the knee .
It's caused when the tissue behind the knee joint becomes swollen and inflamed.. any symptoms other than the fluid-filled swelling at the back of the knee.
A Baker's cyst is a fluid-filled swelling behind the knee. The lump looks most obvious when the child is standing with their. semimembranosus muscle. Patella.