The long bones are those that are longer than they are wide. Long bones, especially the femur and tibia, are subjected to most of the load during daily activities and they are crucial for skeletal mobility. Up to the age of 20 years, RBCs are produced from the red bone marrow of all the bones (long bones and all the flat bones).
After the age of 20 years, RBCs are produced from membranous bones such as vertebrae, the sternum, ribs, scapulas, and iliac bones.
