Interesting. The femur or long thigh bone is the longest single bone. The biggest or heaviest bone is the innomate structure that is the large bowl shaped structure between your two hips. In side this bony cage, human babies develop in a place safe from impact in the early stages of pregnancy. The smallest bone - even smaller than any of the ossicles in your ears - is an exostosis. These are a tiny pearl shaped bony structures that form inside muscles, especially where there is frequent impact during normal activity. Horse riders get these in their gluteal muscles at the point of impact.