The |tibia| is the robust, primary bone of the two in the lower leg. Also called the shin-bone, the |tibia| bears most of the weight. Its head (upper, or proximal, end) articulates with the parallel |fibula| and the |femur| at the |knee joint|. At its distal, or lower, end it articulates with the |fibula| and the |talus| of the ankle. Protruding portions of the lower end of the |tibia|, called the medial malleolus (inside) and lateral malleolus (outside) form the large bumps which characterize the ankle joint.
