“The first shot hit Kennedy’s spine. His elbows were pulled back and up in a common reflex reaction to spinal damage. The bullet put a hole in the knot in Kennedy’s tie, and continued on to hit Connally. That shot killed Kennedy.”
I disagree. His arm movement is no reflex movement; he clearly reaches both hands up and grasps his throat, apparently where the exit wound from the bullet was.
His motion, with elbows high and head flipping back is a classic acute reflex to spinal trauma.
I learned of it by reading the Wound Ballistics Review article on the Kennedy Assassination. The head flip alone was enough to spark thousands of conspiracy theories about the “grassy knoll”.