The fibular head is on the proximal side of the fibula. It provides an attachment point for the biceps femoris, a long muscle connected to the pelvis and the femur that contributes to knee flexion (bending, or decreasing the angle) and hip extension. The fibularis (formerly peroneus) longus muscle is also attached to the fibular head. This muscle passes posteriorly around the lateral malleolus, then goes forward and under the foot and attaches to the first metatarsal on the medial foot. It contributes foot eversion (rotating the foot outward) and plantar flexion (pointing the toes downward), and functions to prevent the foot from rolling inwards as in the common “inversion” ankle sprain. In addition, the fibular head provides an attachment point for the soleus muscle. This is a large muscle that joins with the gastrocnemius muscles to form the calcaneal (Achilles) tendon; working together, these muscles plantar flex the foot at the ankle.
