- Anatomy:
- origin:
- long head: ischial tuberosity and the sacrotuberous ligament;
- short head: lateral lip of linea aspera, lateral supracondyle of femur and lateral intermuscular septum;
- insertion:
- lateral sides of the head of the fibula, lateral condyle of the tibia and the deep fascia on the lateral side of the leg;
- action:
- flexion and lateral rotation of the leg at the knee, extends, adducts and laterally rotates the thigh at the hip;
- short head is primary leg flexor when the long head is placed at disadvantage by the thigh extended;
- reversed origin insertion action:
- the long head gives posterior stability to the pelvis and extends the pelvis on the hip;
- synergists: semimembranosus, semitendinosus , gracilis , sartorius, gastrocnemius;
- nerve supply:
- the bicep femoris is a double muscle receiving 2 nerve supplies;
- long head: sciatic, tibial branch, L5, S1, S2, S3;
- short head: sciatic, peroneal branch, L5, S1, S2;
- see innervation;
- 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
- Hamstring Avulsion:
Coactivation of the hamstrings and quadriceps during extension of the knee.
The effect on gait of lengthening of the medial hamstrings in cerebral palsy.
Computed tomography of hamstring muscle strains.
Hamstring release for knee flexion contracture in spastic adults.
Hamstring injuries: radiographic, conventional tomographic, CT, and MR imaging characteristics.