Case 5

A 20-year-old man attends the ED. He is a rugby player and has had pain in his back for a week following a game. He does not remember any specific injury. There is no significant past medical history and he has no neurological symptoms or signs. 

In view of the possibility of unremembered trauma during the game, you do an x-ray. This is shown on the right. Click the image to see a larger version.

What does the x-ray show?