Biceps femoris

Proximal Attachment: Long head - Ischial tuberosity

                                           Short head - Linea aspera and lateral supracondylar line of femur

Distal Attachment: Lateral side of head of fibula; tendon is split at this site by fibular collateral ligament of knee

Innervation: Long head - Tibial division of sciatic nerve (L₅, S₁, S₂)

                        Short head - Common fibular division of sciatic nerve (L₅, S₁, S₂)

Main Action(s): Flexes leg and rotates it laterally when knee is flexed; extends thigh (e.g., accelerating mass during first step of gait)