arm stuck after an almost-held ball
 

This seems to happens once or twice per season:

A1 and B1 both grab a loose ball. Before a held ball can be called, the stronger A1 pulls the ball loose and pins one of B1's arms against his body.
B1 is now in a position where he could be called for illegal use of hands, but he didn't get there by choice.

What would you call if:

1) B1 is trying to extract his arm but he cannot get it loose
2) B1 continues to fight for the ball or knock it loose with one arm

Held ball, no-call, or foul on B1 in each case?

If A1 is pinning B1's arm, isn't that a foul on A1?

In 1), feel free to call A for a player control foul.
In 2), I'd let it play out.

It sounds to me like A got the ball through the use of "undue roughness." Just because it happened before the official could make the call doesn't mean it's too late to make the call.

How do you figure that? A1 pins B1's arm against his body and B1 did something wrong?

I can see it going both ways....

B1 could, in an effort to get the ball, end up with an arm between A1's arm and A1's body. A1 could turn such that B1 can't get the arm out easily. A1 isn't really holding B1's arm, it is just stuck in an unfortunate place. Still, that could be considered a foul on B1 if there is an advantage (holding A1) since B1 doesn't really have the right to have an arm there.

It could also a foul on A1 if A1 is pinning the arm there an not letting B1 get it free.

I agree with this. Call the held ball which happened first. Contact after the held ball (including pulling away such that a players arm is pinned) is ignored unless intentional or flagrant.

I'm re-reading this and seeing the play differently than my first post (I was imagining B continue to hold onto the ball but get pulled into an awkward position of being pinned). That would be a held ball.

But if A pulled the ball free and B just has an arm stuck, I'm giving the players half a second to react. If B pulls the arm out and A lets him, then I have nothing. If B tries to pull his arm out and A keeps it pinned, then its a foul of A. And if B doesn't attempt to move his arm but instead causes illegal contact then I could see a foul on B.

Call the jump and be done with it.

I'd rather officials discuss plays so we don't have jump balls on plays that shouldn't be ruled jump balls.

This is a good discussion.

Calling the jump avoids all the additional force and interpetations and possible injuries. Jump it and move on.

My play (the original OP) is more like Cameron described, i.e., A1 turns his body and B1's arm inadvertently gets caught. But, It is interesting to see how many of you visualized the play differently.

I am leaning toward a patient no call unless it get rough, and then call the held ball.