Posterior part of knee

The posterior part of knee has a shallow, diamond-shaped depression called the popliteal fossa (a.k.a. knee pit or poplit). Its boundaries and contents are described below:

Boundaries:

• Superomedial: Semitendinosus & semimembranosus

• Superolateral: Tendon of biceps femoris

• Inferomedial: Medial head of gastrocnemius

• Inferolateral: Lateral head of gastrocnemius and plantaris muscle

• Floor: Posterior surface of femur and tibia, knee joint capsule, popliteus muscle

• Roof(superficial to deep): Skin, superficial fascia, deep (popliteal) fascia. The superficial fascia contains important cutaneous vessels and nerves.

Contents:

Major contents (from superficial to deep):

• Tibial and common fibular (common peroneal) branches of sciatic nerve: These are the most superficial. They enter the fossa from under the biceps femoris muscle. The tibial nerve enters the posterior compartment of the leg, whereas the common fibular (common peroneal) nerve divides into deep and superficial peroneal nerves around the neck of fibula.

• Popliteal vein: Lies superficial to the artery. A small saphenous vein drains into it. The popliteal vein exits the fossa through the adductor hiatus, becoming the femoral vein.

• Popliteal artery: This is a distal continuation of femoral artery (which passes through adductor hiatus from adductor canal in the anterior compartment of the thigh). The popliteal artery is the deepest of the neurovascular structures in the popliteal fossa and gives rise to genicular branches for anastomosis around the knee joint.

• Popliteal lymph nodes are also found in the popliteal fossa.