This video is the fourth part in a series discussing musculoskeletal radiology in children. The video was created by Dr. Kai Homer, a resident in Radiology at the University of Alberta with the help of Dr. Adrienne Thompson, a pediatric radiologist at the University of Alberta. The video will focus on musculoskeletal injuries and introduce some cases to help with the understanding of how radiology fits into the whole clinical picture.  This video will discuss ossification centers in the elbow.