Definition
The popliteal fossa is an anatomical structure on the back of the knee. It is diamond-shaped and is bordered on the outside by the biceps femoris muscle – the two-headed thigh muscle. The semimembranosus and semitendinosus muscles are joined inwards, i.e. towards the middle of the knee.
Both ensure flexion and internal rotation of the knee joint. Their tendons are palpable in the hollow of the knee when the knee is tensed. Towards the bottom, the two heads of the gastrocnemius muscle, i.e. the calf muscle, delimit the hollow of the knee. The muscles together form a rhombus, in which several important anatomical structures run.
Anatomy of the hollow of the knee
Several nerves and vessels run through the hollow of the knee, supplying the lower extremity. One of them is the sciatic nerve, or nervus ischadicus, which supplies most of the larger muscles along its supply route from the coccyx to the heel. The sciatic nerve is considered the strongest and thickest nerve in the body.
It runs from its origin in the sacral plexus along the back of the thigh, crosses under the knee flexors, and then splits into the tibial nerve and the common fibular nerve at the popliteal fossa. These in turn supply the muscles of the lower leg. In addition to the sciatic nerve, the popliteal vein and artery pierce the knee in the hollow of the knee.
Both run first as the femoral vein and artery at the front of the thigh until they move through the so-called adductor canal to the back of the knee in the hollow of the knee. From this point on they are also given their new anatomical names. The popliteal artery very soon divides again into anterior and posterior tibial artery.
There are also lymph nodes in the popliteal fossa, which are called Nodi lymphoidei. A distinction is made between deep and superficial popliteal lymph nodes. The popliteal fossa is covered on the outside by a thin layer of skin, which is sensitively supplied by several nerves.
Pain in the popliteal fossaA – Tear of the outer ligament inner ligamentB – Injuries to the menisciC – ArthrosisD – Popliteal cystBaker’s cystE – Trombosis
- Inner meniscus – Meniscus medialis
- Inner band -Ligamentum collaterale tibiale
- Popliteus muscle – popliteus muscle
- Shinbone – Tibia
- Internal calf muscle – M. gastrocnemius, Caput medial
- Outer calf muscle – M. gastrocnemius, lateral caput
- Bilateral Thigh MuscleMusculus biceps femoris
- Semi-tendinous muscle – Musculus semitendinosus
- Thigh bone – Femur
- Posterior cruciate ligament – Ligamentum cruciatum posterius
- Articular cartilage – Cartilago articularis
- Anterior cruciate ligament – Ligamentum cruciatum anterius
- Outer meniscus – Meniscus lateralis
- Outer band – Ligamentum collaterale fibulare
- Fibula – fibula
Pain in the hollow of the knee can have a variety of causes, since a number of important anatomical structures run through it. Pain can also radiate to the upper and lower leg, originate from the front of the knee, or be part of a vascular disease. If the hollow of the knee is swollen and hurts, this may be due to a strain of the surrounding muscles, for example.
A pulled knee is often the result of overexertion during sports activities and disappears after a few days. A typical strain is that it is load-dependent and disappears quickly when the strain is relieved. The situation is different with meniscus damage, which can also take a chronic course over months and years.
Since the menisci in the knee act like a kind of cushion between the thigh and lower leg bones, damage is primarily noticeable when the knee joint is subjected to stress and rotational movements. This stabbing pain usually pulls on the sides of the knee, but can also hurt in the hollow of the knee. For athletes, other rather unlikely causes should also be considered: for example, a hypertrophied, i.e. greatly enlarged muscle can press on the popliteal artery and compress it.
Runners and cyclists often experience irritation of the muscle-tendon transition in the thigh muscles. Typically, a pressure pain occurs when palpating the biceps femoris head. Stretching the leg also hurts.
