How many bones does a typical adult human have?

Answer

Babies are born with about 300 that fuse as they grow.

Context

The figure of 206 describes a typical adult skeleton after growth is complete. An infant's skeleton has more separate pieces, commonly quoted as roughly 270 to 300, because many bones begin as several parts joined by cartilage. During childhood and adolescence these parts ossify and fuse. The skull is a good example: the plates of an infant's skull are separated by flexible seams, and the lower spine's sacrum starts as five vertebrae that merge into one structure in the late teens or twenties.

Because fusion proceeds at different rates, the count is not a fixed number at every age, and it varies between individuals. Some people have an extra rib, an additional vertebra, or small sesamoid bones and sutural bones in the skull and feet that standard counts usually leave out. Anatomy textbooks therefore give 206 as a standard reference value, not a guarantee for every body.

The adult count is usually divided into the axial skeleton of about 80 bones (skull, spine, ribs and breastbone) and the appendicular skeleton of about 126 (limbs and the girdles that attach them). Roughly half of all bones in the body are in the hands and feet, which together contain around 106 of them, a reflection of how many small joints those regions need for fine movement and balance.