tibi/o is a combining form that refers to “tibia (inner lower leg bone)”.
The tibia, also called the shin bone, is the larger of the two bones in the lower leg. Fibula (calf bone) is another bone in the lower leg. A tibia is located closer to the center of your body (medial) than a fibula, extending from beneath the knee to the ankle. The tibia is the second biggest bone in the body and one of the main bones that bear the weight of the body when it stands and moves.