The skeleton which gives a perfect structure to our body is made up of bones. The bone helps in movement and protect our organs as well. The bone will change its strength and shape as we grow older. The bone structure in a child and adult is very different. Bones consist of four materials: periosteum, compact bone, cancellous, and bone marrow.
A child has approximately 300 bones in the body at birth. As the child grows, the bones begin to fuse together, resulting in fewer bones. At the age near to 25, the bone stops growing. Babies start developing their 300 bones during the second trimester. The innermost part is composed of bone marrow, a thick jelly that produces blood cells. As your baby grows inside you, bones begin to replace cartilage in a process called ossification. As your baby gets older, usually between 6 and 18 months, the bones in his skull grow together to cover the soft spots entirely.