| Posterior compartment of thigh | |
|---|---|
 Cross-section through the middle of thethigh. (Posterior compartment is at center bottom.) | |
 Back of left lower extremity. | |
| Details | |
| Artery | Inferior gluteal artery,profunda femoris artery,perforating arteries |
| Nerve | Sciatic nerve |
| Identifiers | |
| Latin | compartimentum femoris posterius |
| TA98 | A04.7.01.003 |
| TA2 | 2637 |
| FMA | 45157 |
| Anatomical terminology | |
Theposterior compartment of the thigh is one of thefascial compartments that contains thekneeflexors andhipextensors known as thehamstring muscles, as well as vascular and nervous elements, particularly thesciatic nerve.
The posterior compartment is afascial compartment bounded byfascia. It is separated from theanterior compartment by two folds ofdeep fascia, known as themedial intermuscular septum and thelateral intermuscular septum.[1]
The muscles of the posterior compartment of the thigh are the:[2][3]
These muscles (or their tendons) apart from the short head of the biceps femoris, are commonly known as thehamstrings. The depression at the back of the knee, orkneepit is thepopliteal fossa, colloquially called theham. 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.[4]
The hamstrings are innervated by the sciatic nerve, specifically by a main branch of it: thetibial nerve. (The short head of the biceps femoris is innervated by thecommon 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.
The arteries that supply the posterior compartment of the thigh arise from theinferior gluteal and the perforating branches of theprofunda femoris artery,[5] a major collateral branch of the femoral artery and part of theanterior compartment of thigh. The femoral artery itself crosses theadductor 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 topopliteal artery.
As with any other fascial compartment, the posterior compartment of thigh can developcompartment syndrome 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.[6]
