The tibia bone plays an important role in weight-bearing and in movement of the knee and ankle joints. It attaches to the femur at the knee joint and the talus at the ankle joint via various ligaments. At the knee joint, the medial collateral ligament and the posterior cruciate ligament attach the tibia to the femur. At the ankle joint, the tibia attaches to the talus through the deltoid ligament.
Many muscles also originate from this bone, such as the tibialis anterior muscle, extensor digitorum longus muscle, soleus muscle, and flexor digitorum longus muscle. Muscles that attach at the tibia include the tensor fascia latae, quadriceps femoris, sartorius, gracilis, semitendinosus, and the popliteus muscle.
At the inner portion of the ankle joint, the tibia forms of the medial malleolus, an obvious bony prominence. Surprisingly, this bone is the second largest bone after the femur.