Leg bone: © MedicalRF.com / ​ age fotostock; close - up: © Alfred Pasieka / ​ Photo Researchers, Inc.; gymnast: Cultura RF / ​ Punchstock
Leg bone: © MedicalRF.com / ​ age fotostock; close - up: © Alfred Pasieka / ​ Photo Researchers, Inc.; gymnast: Cultura RF / ​ Punchstock