How many bones does an adult human have?

An adult human skeleton consists of 206 bones. Babies are born with approximately 270 separate bones, but many of these fuse during childhood and adolescence — for example, the skull starts as several separate plates that eventually fuse (allowing the brain to grow). The process is largely complete by age 25. The longest bone is the femur (thigh bone), averaging 48 cm and capable of supporting 30× body weight. The smallest is the stapes (stirrup bone) in the middle ear, measuring just 2.5–3 mm. The hyoid bone in the throat is the only bone not connected to any other bone. Bones are not static — they are living tissue constantly being remodeled; the entire skeleton is replaced approximately every 10 years. Bones are also surprisingly strong: weight for weight, bone is stronger than steel.