It has two heads of origin;
The fibers of the long head form a
fusiform belly, which passes obliquely downward and lateralward across the
sciatic nerve to end in an
aponeurosis which covers the posterior surface of the muscle, and receives the fibers of the short head; this aponeurosis becomes gradually contracted into a tendon, which is inserted into the lateral side of the head of the
fibula, and by a small slip into the lateral condyle of the
At its insertion the tendon divides into two portions, which embrace the
fibular collateral ligament of the
From the posterior border of the tendon a thin expansion is given off to the
fascia of the leg. The tendon of insertion of this muscle forms the lateral hamstring; the
common fibular (peroneal) nerve descends along its medial border.
The short head may be absent; additional heads may arise from the
ischial tuberosity, the linea aspera, the
medial supracondylar ridge of the femur, or from various other parts.
 The tendon of insertion may be attached to the
Iliotibial band and to retinacular fibers of the
lateral joint capsule.
A slip may pass to the
It is a
composite muscle as the short head of the biceps femoris develops in the
flexor compartment of the thigh and is thus innervated by
common fibular branch of the
sciatic nerve (L5, S2), while the long head is innervated by the
tibial branch of the sciatic nerve (L5, S2).
The muscle's vascular supply is derived from the
anastomoses of several arteries: the
perforating branches of the
profunda femoris artery, the
inferior gluteal artery, and the