Would A Bullet Really Knock You Backwards? DEBUNKED

[Steve Barber]

Neurological Spasm and why I don't buy it.

As JFK passes behind the Stemmons sign his left arm is down by his side.
As he emerges from behind the sign his left arm is in the same position.
Suddenly, it rockets up from his side until both his arms are in this extreme position;



It takes less than half a second to achieve this extreme posture, it is an incredibly rapid movement.
Both elbows appear to extended fully upwards in an extraordinary manner, his hands clench shut apart from the index finger of his left hand which points rigidly, his fists are balled up near his chin and he seems to sit bolt upright.
For the briefest moment he is held in this rigid, extreme posture before relaxing and slumping towards Jackie.
I believe this incredibly rapid movement and extreme posture are a reflex reaction, a neurological spasm, if you will, a feature of which is the stiffening of JFK's upper body.
However, when we examine the head-shot there appears to be no such rigidity present, JFK seems to flop around, his head and arm movement appear completely loose.

There are 16 neck muscles - 4 Suboccipital, 4 Suprahyoid, 4 Infrahyoid and 3 paired sets of Scalene muscles.
These control the various movements of the head - side to side, backwards/forwards and swiveling.
It is an incredibly complex part of the body.
If Neurological Spasm is present during the head-shot, I see no reason why, out of all the neck muscles, only the muscles involving the backwards movement of the head should be involved.
Also, going back to the first point, if these neck muscles were involved why wouldn't they hold the head in the backwards position. This is not shown in the Z-film.

You seem to be proposing a very brief triggering of some very specific muscles, which I, personally, don't buy.
Particularly when there is a far more straight-forward [IMO] explanation.



Different people see different things when analyzing the clip above.
I can only say what I see.
At the moment of the head-shot, the very first movement is forward.
JFK's head seems to nod forward and downward incredibly quickly and then rebound upwards and backwards.
At the moment of the head-shot JFK's head seems to be slumped forward, his chin resting against his body. The massive blow to the back of his head forces his head forwards and downwards, but, because it is already resting on his upper torso/lower neck, his head has nowhere to go and simply rebounds upwards.

No jet effect.
No neurological spasm.

   Hi Dan.  I totally agree that there's no jet effect, but I do believe that
JFK convulsed when the fatal shot was fired.

  In 1978, during an interview with the HSCA,  SS Agent Sam Kinney said that when they were trying to remove JFK from the limousine, JFK's feet were "locked under (Governor Connally's) jump seat". 

  To me, this indicates that JFK convulsed as soon as his brain was destroyed.

[Andrew Mason]

   Hi Dan.  I totally agree that there's no jet effect, but I do believe that
JFK convulsed when the fatal shot was fired.

You cannot conclude that the explosion of matter from the head (some of which landed on the hood of the car and pieces of which landed on the street) did not result in an equal and opposite impulse to the head.  So the question I would have is: how did you determine that the impulse from the ejection of matter from the head was not sufficient to cause the body to move left and to the rear?

[Steve Barber]

You cannot conclude that the explosion of matter from the head (some of which landed on the hood of the car and pieces of which landed on the street) did not result in an equal and opposite impulse to the head.  So the question I would have is: how did you determine that the impulse from the ejection of matter from the head was not sufficient to cause the body to move left and to the rear?

  Perhaps I'm in error.  Perhaps the matter being ejected from the top of the head did contribute to the backward movement.  Not being an expert in the field of what our brain is capable of doing when severely damaged as in this case, however, it makes more sense that the convulsion JFK obviously suffered is the main contributor of the upper body suddenly going backwards during the fatal shot to the head.    Furthermore, There is absolutely no proof that JFK's body moved to the left as a result of the bullet striking his head.  He was already "leaning noticeably to his left". 

[Andrew Mason]

  Perhaps I'm in error.  Perhaps the matter being ejected from the top of the head did contribute to the backward movement.  Not being an expert in the field of what our brain is capable of doing when severely damaged as in this case, however, it makes more sense that the convulsion JFK obviously suffered is the main contributor of the upper body suddenly going backwards during the fatal shot to the head.    Furthermore, There is absolutely no proof that JFK's body moved to the left as a result of the bullet striking his head.  He was already "leaning noticeably to his left".

It is a reasonable inference that his body moved as it did because he had been shot. The evidence shows that a bullet entered the back of the head and exited as we see in the film. There is no evidence of any other impact.  So there is no need to prove "jet effect" or "neurological spasm" or a combination of both as the cause of that movement. But if is definitely because he was hit by a bullet from the rear.

[Steve Barber]

It is a reasonable inference that his body moved as it did because he had been shot. The evidence shows that a bullet entered the back of the head and exited as we see in the film. There is no evidence of any other impact.  So there is no need to prove "jet effect" or "neurological spasm" or a combination of both as the cause of that movement. But if is definitely because he was hit by a bullet from the rear.

 Correct.  He was struck in the back of the head by a singular bullet.  I've been saying it for years, and years.

  The one and only reason for there being any argument about the bullet coming from above and behind is due to the conspiracy theorists whom, since 1964, have argued that the bullet or a second bullet struck him in the head from the front, from the direction of the knoll.  Therefore, this-and this alone--is the reason for discussing the "Jet Effect" and/or the Neuro-muscular reaction.  Those of us who accept the work by the experts in forensics and ballistics, plus using common sense see no need to argue that a singular bullet killed JFK.  With the addition of a document of the 1978 interview Sam Kinney stating that JFK's feet were locked under Connally's jump seat, this only adds further proof that as the fatal bullet struck JFK in the brain, he convulsed, causing his legs to also convulse and move forward, which caused his feet to go completely under Connally's jump seat to the point that they were "locked" under.  This is the first bit of information regarding the body of JFK as the bullets struck, that prove that it was a convulsion that caused his upper body to move backwards against the seat at an estimated 103.3 MPH, not a bullet fired from the front or right side of the limousine.

[Andrew Mason]

Correct.  He was struck in the back of the head by a singular bullet.  I've been saying it for years, and years.

  The one and only reason for there being any argument about the bullet coming from above and behind is due to the conspiracy theorists whom, since 1964, have argued that the bullet or a second bullet struck him in the head from the front, from the direction of the knoll.  Therefore, this-and this alone--is the reason for discussing the "Jet Effect" and/or the Neuro-muscular reaction.  Those of us who accept the work by the experts in forensics and ballistics, plus using common sense see no need to argue that a singular bullet killed JFK.  With the addition of a document of the 1978 interview Sam Kinney stating that JFK's feet were locked under Connally's jump seat, this only adds further proof that as the fatal bullet struck JFK in the brain, he convulsed, causing his legs to also convulse and move forward, which caused his feet to go completely under Connally's jump seat to the point that they were "locked" under.  This is the first bit of information regarding the body of JFK as the bullets struck, that prove that it was a convulsion that caused his upper body to move backwards against the seat at an estimated 103.3 MPH, not a bullet fired from the front or right side of the limousine.

So long as one offers a plausible mechanism to explain the body's motion and so long as there is no evidence at all of a shot from the front right, that is all one needs.  Introducing an uncertain mechanism to explain the body's motion is just giving fuel to the conspiracy fanatics. 

I don't see how the feet being jammed under the front seat helps prove that there was a neuromuscular spasm.  There is nothing to show that JFK did not put his feet there before the shot. There was not a lot of room between the seats.  That would be especially so with Connally in front because he was quite tall and he would likely have pushed the seat back as far as it would go.  Besides, wouldn't a push of the body upward from the feet push the feet down?

The recoil from the exploding head provides a mechanism based on the evidence of what we can actually observe (matter driven out of the head at high speed).  The mechanism of a neuromuscular spasm due to catastrophic loss of brain matter from the right side (which controls the left side of the body) does not have sufficient basis in fact.  It may be possible but we really can't say it occurred.  We can, however, say based on what is observed in the zfilm, that the head received a left-rearward impulse from the matter exploding out of the front right side of his head.

[Steve Barber]

So long as one offers a plausible mechanism to explain the body's motion and so long as there is no evidence at all of a shot from the front right, introducing an uncertain mechanism to explain the body's motion is just giving fuel to the conspiracy fanatics. 

I don't see how the feet being jammed under the front seat helps prove that there was a neuromuscular spasm.  There is nothing to show that JFK did not put his feet there before the shot. There was not a lot of room between the seats.  That would be especially so with Connally in front because he was quite tall and he would likely have pushed the seat back as far as it would go.


The recoil from the exploding head provides a mechanism based on the evidence of what we can actually observe (matter driven out of the head at high speed).  The mechanism of a neuromuscular spasm due to catastrophic loss of brain matter from the right side (which controls the left side of the body) does not have sufficient basis in fact.  It may be possible but we really can't say it occurred.  We can, however, say based on what is observed in the zfilm, that the head received a left-rearward impulse from the matter exploding out of the front left side of his head.

I can!  According to Kinney the feet were "locked".   The only way JFK's feet could've been considered "locked" under that seat was if he'd shoved them up and under the seat, and locked them into that position himself, which I highly doubt that he did.  And the jump seats were not capable of being moved by Connally  any further than where they clicked into place once put into place.  They were connected onto a track, and once locked into place, they could no further to the rear.  You are correct that there wasn't much room between where JFK's feet could be situated and the jump seat.  At least one photograph shows how tight of a squeeze there is between JFK's knees and the back rest of Connally' jump seat.  One photograph during the motorcade shows JFK's knees about an inch away-if that- from the top of Connally's seat.   


  The explosion of head matter exited from TOP of the head--not the "left side"-- but the top. The left side of the skull was basically undamaged same as the brain-and only a fraction of the right top  side of the skull was missing.  Nearly the whole top of his head was gone, according to the top of the head autopsy photos.  Not only can the top of JFK's head be seen flying through the air at a speed of around 80MPH (calculated by Dr. John Lattimer in his book) we can see the skull fragments in the Zapruder film in motion, and a large skull fragment can be seen in both Z 314 between JFK and the Connally's, but the same fragment is captured in later frames bouncing off the top rest of Nellie Connally's seat and tumbling towards the floor of the car. 

[Andrew Mason]

I can!  According to Kinney the feet were "locked".   The only way JFK's feet could've been considered "locked" under that seat was if he'd shoved them up and under the seat, and locked them into that position himself, which I highly doubt that he did.  And the jump seats were not capable of being moved by Connally  any further than where they clicked into place once put into place.  They were connected onto a track, and once locked into place, they could no further to the rear.  You are correct that there wasn't much room between where JFK's feet could be situated and the jump seat.  At least one photograph shows how tight of a squeeze there is between JFK's knees and the back rest of Connally' jump seat.  One photograph during the motorcade shows JFK's knees about an inch away-if that- from the top of Connally's seat.   

Connally was removed first.  The jump seat lifted up so I expect that they would have lifted the seat up to remove JFK.  In any event, we don't really know how JFK's feet were 25 ms after the head shot.  But if you are basing your conclusion of a neuromuscular reaction causing the rear-left motion, it was not because his feet were pinned.  I expect the movement of feet takes significantly longer than 25 ms.

  The explosion of head matter exited from TOP of the head--not the "left side"-- but the top.

I corrected my post shortly afterward to "right side".  You can see the opening up of the right side of his head and you can see a burst of matter over a hemispheric cloud from his head, generally to the right and forward.  That creates an impulse (force x time) in the rear-left direction (ie. opposite to the direction of the matter in the cloud). 

The left side of the skull was basically undamaged same as the brain-and only a fraction of the right top  side of the skull was missing.  Nearly the whole top of his head was gone, according to the top of the head autopsy photos.  Not only can the top of JFK's head be seen flying through the air at a speed of around 80MPH (calculated by Dr. John Lattimer in his book) we can see the skull fragments in the Zapruder film in motion, and a large skull fragment can be seen in both Z 314 between JFK and the Connallys, but the same fragment is captured in later frames bouncing off the top rest of Nellie Connally's seat and tumbling towards the floor of the car.

There is one large fragment that goes up at about a 65 degree angle to the horizontal in the forward direction. It appears to travel about a metre in 25 ms which is 40 m/sec (89 mph), so Lattimer's estimate is about right. The rearward momentum from that is 42% of its total momentum (cos 65°=.42).  If it weighed 100 grams, that piece alone would carry 4 kg m/sec of momentum. So the rear-leftward kick from that would be almost 1/3 of the bullet's incoming momentum.  And that is just one piece of the skull.