Frames

Connally's wrist disappears between z222 and z223, probably due to the bullet driving the hand downward. The coat collar raises and the coat opens, maybe because of a slight shoulder movement.

It is possible that the bullet has struck between 222 and 223.

Connally's lapel flips up and partly hides the shirt for just one frame; his right shoulder goes forward relative to the body, the body rotates left.

The bullet has struck. Connally shows no other reaction than a pure mechanical reaction to the hit. 

Connally's body continues to rotate left. The look on his face is surprise.

JFK also looks surprised, his hands are still going down.

The bullet has gone through both men since a bit more than 55 milliseconds. Their reactions are, until now, purely mechanical : except for the puzzled look on their faces, there is no muscular reaction yet.

Connally slumps and rotates left. His hat is visible as the upward movement of the right hand has begun. Kennedy rotates left and his hands go for his throat.

Both man show for the first time a remarkable muscular reaction.

Connally violently swings his right arm up and forward.

This looks to be a  violent muscular reaction to the bullet that hit his right chest and then gone through his wrist and broken it.

Connally's wrist reappears and goes completely limp, taking a non-natural shape, until it is totally bent at z245. His fingers are still holding the hat which he will keep throughout the film.

While Connally doesn't even notice, he has totally lost control of his wrist.

As from z240

(Warning, 670K GIF)

Connally turns to JFK shouting "No...no"