Anatomy, Bony Pelvis and Lower Limb: Popliteal Region

Excerpt

The popliteal fossa is a shallow depression located posterior to the knee joint. This area is often referred to as the knee "pit" and may develop vascular, nervous, lymphatic, and adipose issues as well as swelling and masses. The fossa houses several important structures that are essential for lower extremity function. Anatomic boundaries of the popliteal fossa include the following:

1. Superomedially, the semimembranosus, and semitendinosus muscles

2. Superolaterally, the biceps femoris muscle (short and long heads)

3. Inferomedial and inferolateral, the medial and lateral heads of the gastrocnemius muscle contribute to the lower border, respectively.

   1. The plantaris muscle also runs deep to the gastrocnemius to form the inferolateral border.

4. The roof of the fossa, proceeding from most superficial to deep, consists of the skin, superficial fascia, and deep (popliteal) fascia.

5. The floor of the fossa includes the popliteal surface of the femur, the capsule of the knee joint, popliteal ligament, and fascia encasing the popliteus muscle.

It is important to understand the involved anatomy of the popliteal fossa because patients could present with posterior knee pain due to multiple etiologies. One of the more common issues involving the posterior knee is a Baker cyst; it has a fluid-filled bursa, which is usually secondary to friction or irritation. Other causes of posterior knee pain could be a popliteal artery aneurysm, lymphadenopathy, thrombophlebitis, and very rarely, sarcomas. Proper diagnosis is essential for effective treatment and management.