Popliteal fossa

Fossa poplitea

Definition

The popliteal fossa (a.k.a. knee pit or poplit) is a shallow, diamond-shaped depression located at the back of the knee. Its boundaries and contents are explained below:

Boundaries:

The boundaries of the popliteal fossa are as follows:

  • Superomedial: semitendinosus and semimembranosus muscles

  • Superolateral: tendon of biceps femoris muscle

  • Inferomedial: medial head of gastrocnemius muscle

  • Inferolateral: lateral head of gastrocnemius muscle and plantaris muscle

  • Floor: formed by the posterior surface of the femur and tibia, capsule of the knee joint, and popliteus muscle

  • Roof: from superficial to deep, it consists of the skin, superficial fascia, and deep (or popliteal) fascia. The superficial fascia contains numerous important cutaneous vessels and nerves.

Contents:

The major contents of the popliteal fossa, from superficial to deep, include nerves, a vein, and an artery:

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

  • Popliteal vein: The vein lies superficial to the artery within the fossa. A small saphenous vein penetrates the deep fascia of the fossa’s roof and drains into the popliteal vein. The popliteal vein exits the fossa by passing through the adductor hiatus, entering the adductor canal, and becoming the femoral vein.

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

  • Popliteal lymph nodes can also be found within the popliteal fossa.

Text written by Muhammad A. Javaid, MD, PhD © 2023 IMAIOS.

  • Drake, R.L., Vogl, A.W. and Mitchell, A.W.M. (2009). ‘Chapter 6: Lower Limb’ in Gray’s anatomy for Students. (2nd ed.) Philadelphia PA 19103-2899: Elsevier, pp.584-585.

  • Hyland, S., Sinkler, M.A. and Varacallo, M. Anatomy, Bony Pelvis and Lower Limb: Popliteal Region. [Updated 2022 Jul 25]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK532891/


Comparative anatomy in animals

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