As has been discussed before, the tibia bone tends to contain a lot of long structures and hence it has a very important role to play when it comes to movement as well as weight-bearing. The tibia is responsible for holding a major share of the weight that comes from the lower leg. The tibia shaft has bone marrow and the color of it is red. This means that the bone marrow also helps in the formation of the red blood cells in the leg region. Another one of the main functions of the proximal and distal tibia is the stabilization of the ankle. Not to mention that it also provides a lot of support to the entire region of the leg.