This inflammation is typically caused by the plica being caught on the
femur, or pinched between the femur and the
patella. The most common location of plica tissue is along the medial (inside) side of the
knee. The plica can tether the patella to the femur, be located between the femur and patella, or be located along the
femoral condyle. If the plica tethers the patella to the femoral condyle, the symptoms may cause it to be mistaken for
chondromalacia. The plica themselves are remnants of the fetal stage of development where the knee is divided into three compartments. The plica normally diminish in size during the second trimester of fetal development, as the three compartments develop into the
synovial capsule. In adults, they normally exist as sleeves of tissue called synovial folds. The plica are usually harmless and unobtrusive; plica syndrome only occurs when the synovial capsule becomes irritated, which thickens the plica themselves (making them prone to irritation/inflammation, or being caught on the femur). ==Diagnosis==