Measurement of the size of the three dimensional space occupied by the portion of the tibia composed of cortical bone. The tibia is the medial and larger of the two bones of the lower leg of bipeds or hindlimb of quadrupeds which articulates with the femur, fibula, and talus. Cortical or compact bone is the relatively solid type of bone tissue found in the middle of long bones which is a hierarchical composite material consisting of a collagen-hydroxyapatite composite at the lowest level forming a complex network of cylindrical units of laminated bone at the highest level.