types of bones
Bones: rigid structures connected by joints to which muscles are attached. The skeleton has more than 200 bones divided into four major groups.
irregular bone 
Bones of varying shapes and sizes, such as the vertebrae and certain bones of the skull or pelvis.
flat bone 
Thin bones that protect certain organs, including most of the bones of the skull as well as the scapula.
short bone 
Bones shaped somewhat like cubes that facilitate flexibility of the joints; examples include the bones of the wrist and ankle.
long bone 
Elongated bone to which powerful muscles, such as those of the leg and arm, are attached.