From birth we've noticed that our son has difficulty with full movement in his arms (one is much more noticeable than the other). He can't straighten his elbow without lifting his shoulder and it's really noticeable in the swimming pool when he's trying to do backstroke/butterfly. He's also broken one scaphoid and badly bruised the other in two separate falls. Does anyone know what might cause these issues? We've asked the GP before and they agreed his movement is abnormal but not indicated why. Thank you.