1 We present the X-rays of a 25-year-old man who fell from a height of approximately 2 metres onto an extended wrist. Plain radiographs (figure 1) show classical signs of a trans-scaphoid perilunate ...

It's one of those things most people remember from their school days. The angles in a triangle always add up to 180˚. And a right-angled triangle always has one angle that is 90°, so the other ...