Bones are rigid organs that form part of the endoskeleton of vertebrates. They function to move, support, and protect the various organs of the body, produce red and white blood cells and store minerals. There are 206 bones in an adult human skeleton.
When affected by nanites, Jeannie Miller had the bones in her legs broken as a means to distract the nanites so they wouldn't attempt to repair the neurological disorder she suffered from and possible kill her. (SGA: "Miller's Crossing")