Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

There is no other way of interpreting this. The cop's arm is holding on to Oswald. It is slipped in-between Oswald's torso and Oswald's arm, and that is how he is holding on to him. So, it has got to be Oswald's arm to the right of the cop's arm. And since that is Oswald's arm, then the part below it must be Oswald's forearm, plus, you can see the bend in the elbow. There is no evidence that Oswald was ever bound like that, and it isn't even possible; it isn't anatomical. 

So, that's the information that the picture provides except that it conflicts with the reality of the situation and with human anatomy.