04/03/2012
Human Anatomy Lovers
((The Popliteal Fossa))
* This diamond-shaped region is posterior to the knee, between the semitendinosus and biceps femoris tendons. It lies posterior to the distal third of the femur, the knee joint and the proximal part of the tibia.
* This fossa appears as a hollow when the knee is flexed.
* Skin and fasciae form the roof of the popliteal fossa (its posterior wall).
* The superficial popliteal fascia contains fat, the small saphenous vein, and three cutaneous nerves.
* The roof is pierced proximally by the posterior femoral cutaneous nerve and distally by the small saphenous vein.
* This vein perforates the deep popliteal fascia and ends in the popliteal vein.
* The deep popliteal fascia forms a strong, dense sheet of deep fascia, which affords a protective covering for the neurovascular structures passing from the thigh to the leg.
* The deep fascia of the thigh is strengthened posterior to the knee by transverse fibres. When the leg is extended, the semimembranosus muscle moves laterally, offering further protection for these structures.
* The popliteal surface of the femur, the oblique popliteal ligament, an expansion of the semimembranosus tendon, and the popliteus fascia form the floor of the popliteal fossa (its anterior wall).
Boundaries of the Popliteal Fossa
* Superolaterally: biceps femoris muscle.
* Superomedially: semimembranosus and semitendinosus muscles.
* Inferolaterally and inferomedially: lateral and medial heads of the gastrocnemius muscle.
Contents of the Popliteal Fossa
* When the muscles forming the boundaries of the fossa are pulled apart, especially the heads of the gastrocnemius, the popliteal fossa and its contents can be observed.
* Although the fossa appears large when this is done, normally the muscles are packed closely together and the fossa is relatively small.
* The contents of the fossa are: fat; the popliteal vessels (artery, vein, and lymphatics); the tibial and common peroneal nerves; the small saphenous vein; the end branch of the posterior femoral cutaneous nerve; and articular branch of the obturator nerve; four to six popliteus lymph nodes; and the popliteus bursa.