Lower limb
Long head of biceps femoris
Caput longum musculi bicipitis femoris
- Origin
- Ischial tuberosity
- Insertion
- Fibular head
- Function
- Extension of the hip, flexion of the knee and external rotation of the lower leg with the knee bent
- Innervation
- Tibial nerve (part of the sciatic nerve), L5-S2
- Movement & chain
- Belongs to the hamstrings; works eccentrically during the swing phase of running to decelerate the knee just before heel contact, which makes this muscle susceptible to injury.
- Palpation
- Can be followed along the posterolateral thigh to the fibular head, readily palpable during resisted knee flexion.
- Clinical
- One of the most common injuries in sprinters and footballers ('hamstring injury'), often at the proximal myotendinous junction.
- Segmental innervation
- L5-S2, part of the myotome testing pattern for knee flexion.
- In clinical practice
- Used in the straight-leg-raise test to assess hamstring flexibility and possible nerve tension pain of the sciatic nerve.
- Region in the model
- Lower limb