Bony landmark · Knee

Head of the fibula

Caput fibulae

The head of the fibula is the knob at the top-outer side of the lower leg, sitting just below and behind the knee joint line. The biceps femoris — the outer hamstring — inserts here alongside the lateral collateral ligament of the knee, and the peroneus longus takes origin just below it. The common peroneal nerve winds around the narrow neck of the bone immediately underneath, where it lies close enough to the surface to be compressed by a tight cast, a crossed leg or a direct knock: the classic cause of a foot that will not lift.