Describe the popliteal fossa and contents.

The popliteal fossa is the diamond shaped space posterior to the knee joint. The roof is formed by the investing layer of deep fascia. The overlying superficial fascia contains the short saphenous vein and the posterior cutaneous nerve of the thigh. The floor is formed by the popliteal surface of the femur, the capsule of the knee joint and the oblique popliteal ligament. Also the anterior most formation of the floor is the popliteus muscle. The walls of the popliteal fossa superiorly are provided by the diverging tendons of the hamstring muscles. The medial border is provided by the tendons of semimembranosos and semitendonosus. The lateral border is formed by the tendons of biceps femoris. Inferiorly the medial and lateral heads of gastrocnemius muscle provide the boundaries. Located medially is the plantaris muscle which also forms this border.

The popliteal fossa contains many structures which enter the anterior and lateral compartments of the leg. The contents include: the politeal artery and vein, the terminal branches of the sciatic nerve namely: tibial and common peroneal nerve. Also fat and the popliteal lymph nodes are found in this region. The popliteal artery is the continuation of the femoral artery after it pierces the tendon of adductor magnus. It travels in the politeal fossa as the deepest structure and leaves the fossa at the inferior angle to split into two branches namely: the anterior and posterior tibial arteries. The popliteal vein is formed from the union of the venae comitantes of the tibial arteries and this leaves the fossa to pierce the adductor hiatus and become the femoral vein. The tibial nerve enters the fossa underneath the hamstring muscles and bisects the fossa leaving at the inferior angle of the fossa beneath the two heads of gastrocnemius. The common peroneal nerve on the other hand, travels laterally under the shade of the tendon of the biceps femoris muscle to gain entry into the lateral compartment of the leg. Here it winds around the neck of the fibula giving off superficial and deep branches.

The politeal fossa acts as a transition point between the thigh and the leg.

Major Points  Where is it located? Roof, Floor, Walls (superior and inferior), contents of the fossa, course of the artery, vein and nerve.

Category: Anatomy Notes