Posterior compartment of thigh
Compartimentum posterius femoris
- Latin synonym: Compartimentum flexorium femoris
- Synonym: Flexor compartment of thigh
Definition
The posterior fascial compartment of the thigh contains the knee flexors and hip extensors.
It consists of the following muscles:
- biceps femoris
- semitendinosus
- semimembranosus
The muscles here (except for the short head of the biceps femoris) are the hamstrings. These muscles are mainly innervated by the sciatic nerve, specifically the tibial nerve. The short head of the biceps femoris is innervated by the fibular nerve. The pit at the back of the knee, known anatomically as the popliteal fossa, is colloquially called the ham. The tendons of the above muscles can be felt as prominent cords on both sides of the fossa—the biceps 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.The arteries of the posterior compartment of the thigh arise from the inferior gluteal and the perforating branches of the profunda femoris.
