Composition

• The skeletal system is composed of bones; connective tissues such as tendons, ligaments and cartilage; and teeth.
  
  

Number of Bones

• Humans are born with more than 300 bones in our bodies. Over time, though, some of these bones fuse together, leaving us with 206 individual bones at adulthood.
  
  

Bone Structure

• Bones have an outer layer of dense, firm compact bone and an inner layer of more flexible spongy bone. Some bones also contain bone marrow in the interior of the spongy bone, which produces cells for the bloodstream.
  
  

Connective Tissues

• Tendons are strong bands that connect bones to muscles to facilitate movement. Ligaments are bands that connect two bones together at a joint, a place where two or more bones meet. Cartilage is the material used to provide a cushion for bones at the joints to prevent friction between them and is also the more flexible material that makes up the ears and nose.
  
  

Fun Facts

• The longest bone, the femur in the leg, provides about one fourth of a person's height. The smallest bone, the stirrup, is buried deep inside the ear and is barely the size of a grain of rice.