The posterior compartment of the thigh is one of the fascial compartments that contains the

knee In humans and other primates, the knee joins the thigh with the leg and consists of two joints: one between the femur and tibia (tibiofemoral joint), and one between the femur and patella (patellofemoral joint). It is the largest joint in the hu ...

flexors and hip extensors known as the hamstring muscles, as well as vascular and nervous elements, particularly the

sciatic nerve The sciatic nerve, also called the ischiadic nerve, is a large nerve in humans and other vertebrate animals. It is the largest branch of the sacral plexus and runs alongside the hip joint and down the right lower limb. It is the longest and widest ...

Structure

The posterior compartment is a

fascial compartment A fascial compartment is a section within the body that contains Skeletal muscle, muscles and nerves and is surrounded by deep fascia. In the human body, the Limb (anatomy), limbs can each be divided into two segments – the upper limb can be di ...

bounded by

fascia A fascia (; : fasciae or fascias; adjective fascial; ) is a generic term for macroscopic membranous bodily structures. Fasciae are classified as superficial, visceral or deep, and further designated according to their anatomical location. ...

. It is separated from the anterior compartment by two folds of

deep fascia Deep fascia (or investing fascia) is a fascia, a layer of dense connective tissue that can surround individual muscles and groups of muscles to separate into fascial compartments. This fibrous connective tissue interpenetrates and surrounds the m ...

, known as the medial intermuscular septum and the lateral intermuscular septum. The muscles of the posterior compartment of the thigh are the: * biceps femoris muscle, which consists of a short head and a long head. *

semitendinosus muscle The semitendinosus () is a long superficial muscle in the Posterior compartment of thigh, back of the thigh. It is so named because it has a very long tendon of insertion. It lies posteromedially in the thigh, superficial to the semimembranosus. ...

* semimembranosus muscle These muscles (or their tendons) apart from the short head of the biceps femoris, are commonly known as the

hamstring A hamstring () is any one of the three posterior thigh muscles in human anatomy between the hip and the knee: from medial to lateral, the semimembranosus, semitendinosus and biceps femoris. Etymology The word " ham" is derived from the Old ...

s. The depression at the back of the knee, or ''kneepit'' is the popliteal fossa, colloquially called the ''ham''. The tendons of the above muscles can be felt as prominent cords on both sides of the fossa—the biceps femoris tendon on the lateral side and the semimembranosus and semitendinosus tendons on the medial side. The hamstrings flex the knee, and aided by the gluteus maximus, they extend the hip during walking and running. The semitendinosus is named for its unusually long tendon. The semimembranosus is named for the flat shape of its superior attachment.

Innervation

The hamstrings are innervated by the sciatic nerve, specifically by a main branch of it: the tibial nerve. (The short head of the biceps femoris is innervated by the common fibular nerve). The sciatic nerve runs along the longitudinal axis of the compartment, giving the cited terminal branches close to the superior angle of the popliteal fossa.

Blood supply

The arteries that supply the posterior compartment of the thigh arise from the inferior gluteal and the perforating branches of the profunda femoris artery, a major collateral branch of the femoral artery and part of the anterior compartment of thigh. The femoral artery itself crosses the adductor hiatus to enter the posterior compartment at the level of the popliteal fossa, giving branches that supply the knee. This crossing marks the point in which the vessel changes its name to popliteal artery.

Clinical significance

As with any other fascial compartment, the posterior compartment of thigh can develop

compartment syndrome Compartment syndrome is a serious medical condition in which increased pressure within a Fascial compartment, body compartment compromises blood flow and tissue function, potentially leading to permanent damage if not promptly treated. There are ...

when pressure builds up inside it, reducing the ability of arteries to transport blood to muscles and nerves. In acute cases, this is most frequently a consequence of trauma.

References

External links