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 human leg, 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 join ...
flexors
A flexor is a muscle that flexes a joint. In anatomy, flexion (from the Latin verb ''flectere'', to bend) is a joint movement that decreases the angle between the bones that converge at the joint. For example, one’s elbow joint flexes when one ...
and
hip extensors known as the
hamstring muscles, as well as vascular and nervous elements, particularly the
sciatic nerve.
Structure
The posterior compartment is a
fascial compartment bounded by
fascia
A fascia (; plural fasciae or fascias; adjective fascial; from Latin: "band") is a band or sheet of connective tissue, primarily collagen, beneath the skin that attaches to, stabilizes, encloses, and separates muscles and other internal organ ...
. 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 ...
, known as the
medial intermuscular septum and the
lateral intermuscular septum.
The muscles of the posterior compartment of the thigh are the:
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biceps femoris muscle, which consists of a short head and a long head.
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semitendinosus muscle
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semimembranosus muscle
These muscles (or their tendons) apart from the short head of the biceps femoris, are commonly known as the
hamstring
In human anatomy, a hamstring () is any one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris). The hamstrings are susceptible to injury.
In quadrup ...
s. The depression at the back of the knee, or ''kneepit'' is the
popliteal fossa
The popliteal fossa (also referred to as hough, ">/sup> or kneepit in analogy to the cubital fossa) is a shallow depression located at the back of the knee joint. The bones of the popliteal fossa are the femur and the tibia. Like other flexion ...
, 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 anterior compartment of thigh contains muscles which extend the knee and flex the hip.
Structure
The anterior compartment is one of the fascial compartments of the thigh that contains groups of muscles together with their nerves and blood s ...
. 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
The popliteal artery is a deeply placed continuation of the femoral artery opening in the distal portion of the adductor magnus muscle. It courses through the popliteal fossa and ends at the lower border of the popliteus muscle, where it branches ...
.
Clinical significance
As with any other fascial compartment, the posterior compartment of thigh can develop
compartment syndrome
Compartment syndrome is a condition in which increased pressure within one of the body's anatomical compartments results in insufficient blood supply to tissue within that space. There are two main types: acute and chronic. Compartments of th ...
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.
See also
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Fascia lata
The fascia lata is the deep fascia of the thigh. It encloses the thigh muscles and forms the outer limit of the fascial compartments of thigh, which are internally separated by the medial intermuscular septum and the lateral intermuscular sept ...
References
External links
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knee/muscles/thigh3at the
Dartmouth Medical School's Department of Anatomy
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Anatomy