Anatomy and Contents of the Popliteal fossa

Courtesy: Prof Nabil Ebraheim, University of Toledo, Ohio, USA

Popliteal fossa is a shallow depression located at the back of the knee joint , bounded by biceps femoris superolaterally ,semimembranosus and semitendinosus superomedially . Inferior boundary of this space is made by the medial and lateral heads of gastrocnemius muscle .
Coming to the base of the popliteal fossa :popliteal surface of the femur ,capsule of the knee joint , oblique popliteal ligament,and the strong fascia covering the popliteus muscle constitute the floor.Popliteal artery, popliteal vein ,small saphenous vein ,tibial nerve and the common peroneal nerve are the structures located within the popliteal fossa in medial to lateral direction. Skin and the deep popliteal fascia form the roof .
Baker’s cyst otherwise called as popliteal cyst is an important clinical entity related to the popliteal fossa ,located between semimembranosus and the medial gastrocnemius ,it is commonly caused by knee arthritis or a meniscal tear.The cyst is connected to the knee joint through a valvular opening .knee effusion from intra articular pathology allows the fluid to go through the valve to the cyst in one direction.