Biceps femoris
Latin: M. biceps femoris sinistra
Location: Thigh
Paired structure: one on the left and one on the right side of the body.
View the biceps femoris in 3DOrigin
Long head: ischial tuberosity (with semitendinosus). Short head: linea aspera of the femur (lateral lip).
Insertion
Lateral side of the head of the fibula (with the fibular collateral ligament).
Action
Flexes the knee and extends the hip (long head); laterally rotates the flexed knee. The short head is a knee-only flexor.
Nerve supply
Long head: tibial nerve (L5–S2). Short head: common peroneal nerve (L5–S2) — the hamstrings' dual supply.
Blood supply
Perforating branches of the profunda femoris.
Clinical relevance
Sprinting hamstring strains tear the left biceps femoris most often at the musculotendinous junction; its tendon runs just behind the fibular collateral ligament — a surgical landmark for lateral meniscus repair.
Educational anatomy reference, not medical advice. About this content.