Posterior Thigh Muscles
Posterior compartment of the thigh muscles are collectively referred to as the "hamstrings"* muscles.
They produce thigh extension and leg flexion.*
From lateral to medial, the posterior compartment muscles are:
Biceps femoris, long head:
Originates on the ischial tuberosity*
Biceps femoris, short head:
Originates on the linea aspera* of the femur.
Both heads of biceps femoris insert on the fibular head, which allows them to laterally rotate the leg.
Semimembranosus & Semitendinosus both
Originate on the ischial tuberosity*
Insert on the medial tibial condyle,* which allows them to medially rotate the leg.
The tendon of semitendinosus blends with the tendons of gracilis and sartorius to form the “pes anserinus” (Latin for “goose’s foot”).
Posterior thigh innervation is via the sciatic nerve, which arises from the sacral plexus.
Indicate that the tibial division innervates the long head of biceps femoris, semitendinosus, and semimembranosus;
The common fibular division (aka, common peroneal division) innervate the short head of biceps femoris.
Innervation
Posterior Thigh Muscles
Semimembranosus & Semitendinosus both
Originate on the ischial tuberosity*
Insert on the medial tibial condyle,* which allows them to medially rotate the leg.
- Semitendinosus lies superficial to semimembranosus.
- Semitendinosus is relatively thin, and terminates in a long cord-like tendon.
- Semimembranosus is relatively wide, and terminates in a flat, membranous tendon.
The tendon of semitendinosus blends with the tendons of gracilis and sartorius to form the “pes anserinus” (Latin for “goose’s foot”).
Innervation