General

• There are 206 bones in an adult human body.
  A baby has more bones (about 300) than an adult. This is possible because throughout the growth years, many of the bones of the skull and spine fuse together.
  Bones do not move, they need the help of the muscles attached to the bones, which is why the muscular system and skeletal system are often merged to be called the musculoskeletal system.
  Bones are alive. They are made up of living cells, which is why they can grow and repair themselves.
  
  

Size

• The femur bone in the leg is the longest bone in the body. It is about one-quarter of a person's overall height.
  The smallest bones in the body are the three bones of the middle ear: the anvil, the hammer and the stirrup, which is the smallest.
  The largest bone in the body is the pelvic bone.
  
  

Bones

• The bone most frequently broken is the collar bone, also known as the clavicle.
  The only bone not connected to any other bone is the hyoid bone located in the throat.
  There are two types of bone tissue, compact hard bones and spongy bone. Most bones contain both types of tissue.
  Over half of the bones in the body are found in the hands and feet.
  Humans and giraffes have the same number of bones in their necks. The giraffe vertebra are just much longer.
  
  

Bone Marrow

• Bones are filled with a substance called bone marrow, which is critical for the production of red and white blood cells.
  There are two types of bone marrow. Red marrow produces blood cells and yellow marrow produces mostly fatty cells.
  At birth, all bone marrow is red.
  
  

Cartilage

• The ears and the end of the nose don't have bones. These part of the body are given their shape by cartilage.
  Cartilage is more flexible than bone, allowing movement and the ability to bend.
  Cartilage degrades faster than bone, which is why many human remains are found without a nose or ears.
  Cartilage contains no blood vessels or nerve cells.
  Embryos contain cartilage, not bones.