For those not used to looking at xrays of children, don't forget the normal ossification centres and how to differentiate these with acute injuries. Most people seem to remember these using the mnemonic CRITOE:
- Radial head
- Internal condyle
- External condyle
Some people use medial/lateral instead of internal/external. During my paediatric orthopaedics term I was taught the mnemonic "Come Ride My Tool Of Love" which is both less appropriate and more memorable (probably because it is less appropriate).
Development of these centres progresses in this order with age, with the general guide being at ages 1-3-5-7-9-11 years old. Boys may develop a little later (on the even years). It is important to note that, although the capitellum is normally present by age 2, the other centres may not develop on schedule, and radial head development may even be delayed until age 6 or so. And then they might all happen over a shorter period.
The importance, however, lies more in the order. This allows you to determine if an ossification centre should be present based on age and the presence of other centres, and this may help you identify whether a floating fragment of bone is in fact a fracture or normal.
This boy has an ossified capitellum, but no evidence of radial head ossification yet.
There is a lucency at the lateral condyle. Since we know that the ossification centre here will not yet be visible (as it is the last to develop), this is a fracture of the lateral condyle. He had a backslab applied and was referred for follow up with the paediatric orthopods.
There are a lot of resources about ossification centres. I use Radiopaedia a lot for radiology-related learning, Don't Forget the Bubbles for all things paediatric, and Ortho Bullets for quick updates on orthopaedic problems.