The human locomotor system tries to adapt to the new structural and functional conditions that appear during development.The term osteochondrosis is used to describe a group of diseases that originate during the process of bone growth. Many of them are considered rare due to the scarce reports that are usually found in the scientific literature, and for the first time they are collected together in this volume. This book aims to be a reference manual, not a treatise. It only approaches a frequent health problem in children and adolescents that will continue to exist for many years and whose misdiagnosis can trigger serious physical and psychological consequences for the patient and his or her family.