Biceps femoris muscle/عضلة ذات الرأسين الفخذية/股二头肌(Gǔ èr tóu jī)

Biceps Femoris is one of the three muscles which form the hamstring group forming the back of the thigh. 

The muscle is often described as having a long head (the attachment from the ischium) and a short head (attached to the femur).

ORIGIN

Long head: upper inner quadrant of posterior surface of ischial tuberosity. Short head:middle third of linea aspera, lateral supracondylar ridge of femur

INSERTION

Styloid process of head of fibula. lateral collateral ligament and lateral tibial condyle

ACTION

Flexes and laterally rotates knee. Long head extends hip

Lieing-Hamstring-Stretch.

NERVE

Long head: tibial portion of sciatic nerve. Short head: common peroneal portion of sciatic nerve (both L5, S1)

- Function:

- pes anserinus counterpart on the lateral side of knee is strong biceps femoris insertion into fibular head, lateral tibia, and posterolateral

capsular structures;

- it is strong flexor of knee w/ simultaneous external rotation of tibia;

- provides rotary stability by preventing forward dislocation of tibia on femur during flexion;

- its contributions to arcuate complex to the arcuate ligament complex at the posterolateral corner of the knee also provide varus as well

as a rotatory stability of the knee

Active Biceps Femoris Stretch