JFK's Head Snap and the Implausible Jet-Effect and Neurospasm Theories

[Michael T. Griffith]

Speaking of human neuromuscular reaction times, the following does not deal with Kennedy’s head movement, but it does deal with the much more  modest movement of his right hand that begins in Z225, even if the movement was involuntary. Experts for the prosecution and the defense both agreed that at least 200 milliseconds, or around four Zapruder frames, would have elapsed between bullet impact and JFK’s reaction, even if the movement was reflexive/involuntary.

Dr. Robert Piziali, a wound ballistics expert, stated under cross examination at the 1992 American Bar Association mock Oswald trial that if Kennedy began to react to a wound at Z225, this would mean the bullet could have struck him no later than Z221. Dr. Piziali, who supervised the Failure Analysis research for the 1992 mock Oswald trial, explained there would have been a delay of four frames, or about 200 milliseconds, between the bullet's impact and Kennedy's reaction to it with his right hand. He said a "reflexive reaction" to bullet impact would take "approximately 200 ms” (see trial transcript in Harrison Livingstone, Killing the Truth, New York: Carroll & Graf, 1993, pp. 224-236; see also http://www.patspeer.com/chapter12%3Athesingle-bullet%22fact%22).

Ballistics expert Dr. Roger McCarthy, testifying for the defense in the 1992 mock Oswald trial, agreed that it would have taken a minimum of 200 milliseconds, or right around four frames, for Kennedy to react, even involuntarily, as we see him start to do in Z225:

Mr. CHESLER. Now, what I'd like to do is, is move to the very next frame, 225. How much time elapsed on that day between time frame 224 was filmed and the time that frame 225 was filmed?

Dr. McCARTHY. About 56 milliseconds. This camera is running at a shade more than 18 frames/second, so between any 2 frames there's about an 18th of a second or 56 thousandth of a second. . . .

Mr. CHESLER. Now, Dr., based upon that, do you have a conclusion or an opinion as to when the President was hit with the bullet--how much before this point?

Dr. McCARTHY. Yes, as I think Dr. Piziali accurately indicated, there is a latency or a delay of about 200 milliseconds between the time that a message is delivered by either traumatic shock to the spine or by your mind to a muscle before you can get movement. . . . It takes about a fifth of a second to get all the hardware up to full power--to get the muscles to move.

Mr. CHESLER. Now, Dr., if, then, the President was hit 200 milliseconds before the movement on [frame] 225, how many frames back in the film would that be?

Dr. McCARTHY. That would be at 221 at a minimum [i.e., at the latest, and notice this is just based on timing it from a reaction at Z225]

Mr. CHESLER. And at 221 he's behind the sign, is that correct?

Dr. McCARTHY. Yes.

Mr. CHESLER. Alright. If he was hit at 221 and the Governor was hit at 224 according to the prosecution, then could they have been hit by the same bullet?

Dr. McCARTHY. No. (Killing the Truth, pp. 235-236)

This agreement by prosecution and defense experts on the time required for Kennedy to involuntarily move his right arm after bullet impact casts further doubt on the specious claim that a neuromuscular reaction could have caused JFK's backward head movement in the space of just 40-50 milliseconds. And this is not to mention the observable fact that Kennedy's reaction looks like nothing like the goat's reaction in the goat films.

[Thomas Graves]

I told you that if could not maintain civility, I would not respond to you. Go try to find someone else who will sink down to your level. I will not waste time dealing with such juvenile rudeness. Goodbye.

Dear Mike,

Well-spoken and I totally agree, but you do have a typo.

(You left out the word "you".)

--  MWT 

PS  Are you really a Trump supporter?

You do realize he's a traitor, don't you?

[Tim Nickerson]

Speaking of human neuromuscular reaction times, the following does not deal with Kennedy’s head movement, but it does deal with the much more  modest movement of his right hand that begins in Z225, even if the movement was involuntary. Experts for the prosecution and the defense both agreed that at least 200 milliseconds, or around four Zapruder frames, would have elapsed between bullet impact and JFK’s reaction, even if the movement was reflexive/involuntary.

Dr. Robert Piziali, a wound ballistics expert, stated under cross examination at the 1992 American Bar Association mock Oswald trial that if Kennedy began to react to a wound at Z225, this would mean the bullet could have struck him no later than Z221. Dr. Piziali, who supervised the Failure Analysis research for the 1992 mock Oswald trial, explained there would have been a delay of four frames, or about 200 milliseconds, between the bullet's impact and Kennedy's reaction to it with his right hand. He said a "reflexive reaction" to bullet impact would take "approximately 200 ms” (see trial transcript in Harrison Livingstone, Killing the Truth, New York: Carroll & Graf, 1993, pp. 224-236; see also http://www.patspeer.com/chapter12%3Athesingle-bullet%22fact%22).

Ballistics expert Dr. Roger McCarthy, testifying for the defense in the 1992 mock Oswald trial, agreed that it would have taken a minimum of 200 milliseconds, or right around four frames, for Kennedy to react, even involuntarily, as we see him start to do in Z225:

This agreement by prosecution and defense experts on the time required for Kennedy to involuntarily move his right arm after bullet impact casts further doubt on the specious claim that a neuromuscular reaction could have caused JFK's backward head movement in the space of just 40-50 milliseconds. And this is not to mention the observable fact that Kennedy's reaction looks like nothing like the goat's reaction in the goat films.

"Movement caused by the sudden interruption of the spinal nerves below the cord injury would have appeared much faster than a startle reflex, probably even faster than a spinal reflex. In a spinal reflex, the nerve impulse travels from the hand to the spine and back down to the muscles without having to go through the brain. This typically takes less than one-quarter of a second, or about four frames in the Zapruder film. In a direct reaction to a spinal injury, the uninterrupted impulse only has to make the 'outward' path to initiate the movement of the arm. This would probably take a little more than half the time of a spinal reflex." -- The JFK Myths: A Scientific Investigation of the Kennedy Assassination, by Larry Sturdivan, page 158

https://www.amazon.com/JFK-Myths-Scientific-Investigation-Assassination/dp/1557788472

[Dan O'meara]

Experts for the prosecution and the defense both agreed that at least 200 milliseconds, or around four Zapruder frames, would have elapsed between bullet impact and JFK’s reaction, even if the movement was reflexive/involuntary.

“The average reaction time for a visual stimulus is about 250 milliseconds. The average reaction time for an auditory stimulus is about 170 milliseconds and for a touch stimulus 150 milliseconds.” [https://www.onaverage.co.uk/other-averages/average-reaction-time]

The touch stimulus of 150 milliseconds refers to an external stimulus being applied and the reaction to it. JFK's 'hand snap' is not a reaction, it is a reflex and to imagine there is no difference between a reaction and a reflex displays a deep lack of understanding regarding this issue. The 'hand snap' is a Withdrawal (Nociceptive Flexion) Reflex in response to a stimulus applied directly to the Central Nervous System (CNS). With this type of reflex the time taken for the stimulus to be detected and reach the CNS for processing is eliminated as the stimulus is being applied directly to the CNS. This type of reflex is far quicker than a reaction.
The 200 millisecond measurement you quote is hopelessly outdated and is reflected in your analysis.

[Tim Nickerson]

“The average reaction time for a visual stimulus is about 250 milliseconds. The average reaction time for an auditory stimulus is about 170 milliseconds and for a touch stimulus 150 milliseconds.” [https://www.onaverage.co.uk/other-averages/average-reaction-time]

The touch stimulus of 150 milliseconds refers to an external stimulus being applied and the reaction to it. JFK's 'hand snap' is not a reaction, it is a reflex and to imagine there is no difference between a reaction and a reflex displays a deep lack of understanding regarding this issue. The 'hand snap' is a Withdrawal (Nociceptive Flexion) Reflex in response to a stimulus applied directly to the Central Nervous System (CNS). With this type of reflex the time taken for the stimulus to be detected and reach the CNS for processing is eliminated as the stimulus is being applied directly to the CNS. This type of reflex is far quicker than a reaction.
The 200 millisecond measurement you quote is hopelessly outdated and is reflected in your analysis.

Sturdivan's "uninterrupted impulse" theory would also cut the response time in half. However, I'm not fully onboard with that theory. It doesn't accurately account for Connally's rapid reaction. Sturdivan wrongly has Connally reacting later than Kennedy.

[Thomas Graves]

Another attempt to poison the well with a completely off-topic smear.

Elliott does that a lot.

Iacoletti,

And your comments from the peanut gallery are somehow "on topic"?

--  MWT 

[Dan O'meara]

Sturdivan's "uninterrupted impulse" theory would also cut the response time in half. However, I'm not fully onboard with that theory. It doesn't accurately account for Connally's rapid reaction. Sturdivan wrongly has Connally reacting later than Kennedy.

Both men are shot through in z224, the time it takes for the bullet to pass through both men is so small we can, for our purposes, consider it instantaneous. In z225 JFK's hand begins to snap shut, this is a reflex that probably indicates the bullet that has passed through him, very close to his spine and high up on his back, has severed one of the plexus of nerves that emanates from this part of the spinal column and are directly connected to the hand.
However, it's not a reaction to the bullet, it's a reflex. We see the reaction of both men to being shot in z226, Kennedy's left elbow is raised into view, his right hand has snapped fully shut and is moving towards his throat. Connally's Stetson begins to shoot up, this is the first moment of the sudden thrashing around and twisting in his seat that can clearly be seen in the full Zfilm.

[Joe Elliott]

Both men are shot through in z224, the time it takes for the bullet to pass through both men is so small we can, for our purposes, consider it instantaneous. In z225 JFK's hand begins to snap shut, this is a reflex that probably indicates the bullet that has passed through him, very close to his spine and high up on his back, has severed one of the plexus of nerves that emanates from this part of the spinal column and are directly connected to the hand.
However, it's not a reaction to the bullet, it's a reflex. We see the reaction of both men to being shot in z226, Kennedy's left elbow is raised into view, his right hand has snapped fully shut and is moving towards his throat. Connally's Stetson begins to shoot up, this is the first moment of the sudden thrashing around and twisting in his seat that can clearly be seen in the full Zfilm.

Hello Dan

The best study on the exact timing of the bullet that struck both men was conducted by Dr. Lattimer back in the 1990’s. He used neck from a hog and a rib cage from a hog. The rib cage had a shirt button around it, a neck tie was knotted and a coat placed over it, as a model for the Governor. A Carcano rifle with WCC/MC bullets was fired through both the “neck” and the “torso” models, separated by 24 inches.

It is all described below:

https://mcadams.posc.mu.edu/Lattimer.txt

This test showed that the coat’s maximum movement, its maximum bulge, occurred 3/30 of a second after bullet impact. It appears the movement was caused not by the bullet, which passed through at 0/30 seconds, slicing through the coat without moving it much, but by debris that came flying out of the chest wound and struck the coat, causing the whole right side of the coat to swing forward and perhaps the lapel to flip upward. It’s hard for me to tell what happened in the Zapruder film other than the coat moved.

The coat movement reached its peak at z224. 3/30 of a second before, or 1/10 of a second before, corresponds to Frame 222. Until better tests are run than those conducted by Dr. Lattimer, Frame 222 has to be considered as the most likely moment of impact.

This also corresponds with the strong camera jiggle of Mr. Zapruder’s camera that occurs at z227. The Camera Jiggle, judging by the strong camera jiggle at z318, should occur 5 to 6 frames after a bullet strike, so this corresponds to frame 222 better than frame 224.

So, the bullet was fired at z220. The bullet struck both men at frame 222. By frame 224 the coat’s forward movement reaches its maximum. And by frame 226, both the President’s and the Governor’s right arm abruptly starts rising.



As an aside, I would urge caution in putting the bullet impact too late. A strike at z224, or even z223, opens the door up to CTers to go to their standard claim “The reactions are too fast to be humanly possible”. Popular for both the z222 and the z312 bullet strike. They would make the same claim about a third strike on the President or the Governor if we LNers believed there was a third strike. Frame 222 is the best estimate. I’m not placing it earlier than it should be, except a CTer might point out that z222 is 110 milliseconds before z224, not 100. Even so, Frame 222 is the best estimate we have, subject to future testing of the nature Dr. Lattimer carried out.