Bone

There are two-hundred and six bones in the adult human body^1. . Children have more bones (270 as an infant), as bones in the skull are separate and have not yet fused together (ossification). These bones make up the skeletal system which helps support the body and aid in movement. In the human skeleton, there are two main types of bone: long bones and flat bones^2., and three others, (short, irregular, sesmoif). Long bones, such as the humerous, are made up of a long shaft made of compact bone and contain a cavity which is filled with bone marrow. Flat bones are mainly found in the skull and are made of two thin layers of compact bone, with a layer of cancellous bone in between them^3.. 

References

1.Denise M. Covert, R.N.. (2011). How Many Bones Are There in the Human Body?. Available: http://howmanyarethere.net/how-many-bones-are-there-in-the-human-body/. Last accessed 23rd Oct 2012

2.Biology for the Medical Sciences, P. Bradley & J. Calvert

3.http://www.teachpe.com/anatomy/types_of_bones.php (25/10/2012)