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

[Joe Elliott]

Some of your arguments are valid. Some of them are erroneous. And some of them are overly simplistic. As just one example, McClellan was very anti-slavery, but he was also a constitutionalist. He was perfectly okay with ending slavery as long as it was ended constitutionally. As long as slavery was legal, he did not feel authorized to use extra-legal means to free slaves, but he personally detested slavery.

My arguments are true. In 1861, the Southern stated they seceded in order to maintain slavery. Four of the seceding states stated their reasons in their “Declaration of Causes” official statements, emulating the 1776 “Declaration of Independence”.

https://www.battlefields.org/learn/articles/declarations-causes

There are many complaints about the Northern threat to the institution of slavery. And many complaints about Northern states exercising their own “State Rights” and passing laws that conflict with Federal Law, the “Fugitive Slave Act” of 1850.

But not once is the word ‘Tariff’ mentioned.

I assume the 7 other seceding states would have issued similar statements, but were too busy, or maybe deep down too ashamed to express their base motives in an official declaration.


It was only after 1865 that the south started to come out with “Declaration of Causes”, Version 2.0, which now gave more noble reasons for Secession. To protect States Rights. To avoid high tariffs. And slavery was a more minor issue. And until recently, these were the reasons taught in our schools. And is still being pushed by some people.



McClellan detested slavery. So did a lot of people, in both the North and South, who thought slavery should continue, as did McClellan. So, again, I am not impressed with McClellan’s views. And slavery was ended permanently though constitutional means so why should anyone complain?

[Michael T. Griffith]

Below is one of Dr. Art Snyder’s critiques of the jet-effect and neuromuscular-reaction theories. Dr. Snyder is a former physicist at Stanford University. He received his PhD in physics from the University of Illinois. He taught physics at Indiana University before joining the staff at Stanford University. Dr. Snyder wrote this critique in 1998 in response to Gerald Posner’s arguments about JFK’s head snap in Case Closed:

The head snap refers to the backward motion of President Kennedy’s head seen in the Zapruder film. As Posner puts it, “But if the President was struck in the head by a bullet fired from the rear, then why does he jerk so violently backward on the Zapruder film which recorded the assassination? To most people, the rapid backward movement at the moment of the shot means the President was struck from the front.” Posner begins by trying to dismiss the significance of the head snap with a quote from respected forensic pathologist Dr. Michael Baden: “People have no conception of how real life works with bullet wounds. It’s not like Hollywood, where someone gets shot and falls over backwards.” Dr. Baden is right about people, but heads are more than an order of magnitude lighter than a person. The velocity imparted to a head by a stopping bullet is given by conservation of momentum:

V head = V bullet (M bullet/M head)

where V is velocity and M is mass. For a 10 gm bullet moving at 550 meter/sec hitting a 5 kg head, this is -1 meter sec, or to put it another way ~2.4 inches per Zapruder frame.

Having used Dr. Baden to dismiss the possibility that a bullet strike could cause head motion, Posner twists around and in the next paragraph notes that Itek Corporation, using a “computer enhancement” (Itek, 1975), discovered that JFK “first jerked forward 2.3 inches before starting his rapid movement backward.” Itek did not “discover” this forward motion. Cal-Tech physicist Richard Feynman noticed it in 1966 when David Lifton showed him the Zapruder frames published in Life (Lifton, 1980, 48). Warren critic Josiah Thompson published measurements made on black and white copies in the 1967 book Six Seconds in Dallas (Thompson, 1967, 90).

The measurements of Itek and Thompson are almost inconsistent with a shot from a Mannlicher-Carcano. The motion is so large that nearly all the momentum of the bullet is needed to account for it. However, quantitatively Thompson and Itek were mistaken. The apparent motion between Zapruder frames Z312 and Z313 is an artifact of the blurring of frame Z313. This is not to say that JFK’s head did not move forward between frames Z312 and Z313, but that the Z313 blur obscures the motion so that it cannot be measured using these frames. The actual forward motion (~0.3 meter/sec) can be estimated by comparing Z312 to Z314. It is about 1/3 the value obtained using the Itek or Thompson measurements—consistent with a Carcano bullet imparting ~1/3 its momentum and ~1/2 its energy.

What is the purpose of Posner’s dance around the forward motion? He trots out Dr. Baden to deny that the direction of motion tells us anything, then uses the observed forward motion to verify a shot from the rear. None of this explains why the head went backward ~100 msec later.

An explanation for the backward proposed by Nobel Laurette Luis Alvarez, in his 1976 article in the American Journal of Physics. Posner’s description of Alvarez’s work is ludicrous:

“Dubbed the ‘jet effect,’ Alvarez established it both through physical experiments that recreated the head shot and extensive laboratory calculations. He found when the brain and blood tissue exploded out of JFK’s head, they carried more momentum than was brought in by the bullet—in an opposite direction—as a rocket does when its jet fuel is ejected.”

The “recreation” of the head shot consisted of shooting 2-3 pound melons wrapped in strapping tape with the wrong gun (30.06) and the wrong ammunition (hunting instead of jacketed military ammunition). The “extensive laboratory calculations” consisted of a “back of the envelope calculation” Alvarez did in his hotel room at the 1969 meeting of the American Physical Society in St. Louis (Alvarez, 1976, 819). The calculation demonstrates that the jet-effect is kinematically allowed. It does not establish that ejected material “carried more momentum than was brought in by the bullet,” but only that this is possible.

The possibility of the jet-effect arises from the relationship between kinetic energy and momentum:

P=/2ME

Where P is momentum, M is mass and E is kinetic energy. If a large enough mass is ejected, it can carry more momentum than the income bullet deposits using only a fraction of the bullet’s energy. For example, if 0.2 kg of material were expelled carrying 10% of the bullet’s energy, it would carry a 7.8 kg-m/sec of momentum—enough to overcome the maximum possible momentum a Carcano bullet can deposit (6 kg-m/sec). Kinematics allows jet-effect to occur but only the detailed interaction of the bullet with the target determines if it actually occurs under a given set of circumstances.

Alvarez’s melon shooting experiment demonstrated that there are circumstances under which the jet-effect occurs. Dr. J.K. Lattimer (1980) did experiments using the correct rifle and ammunition. Lattimer claimed his targets—whether skulls or melons—“always” went backwards. Edgewood Arsenal did experiments on skulls (Edgewood 1964; HSCA, Vol. 1, 404). All skulls shot by Edgewood moved away from the shooter [i.e., they moved in the same direction the bullet was traveling].

Since the publication of Case Closed, there have been by Dr. Doug DeSalles and Dick Hobbs (DeSalles and Hobbs, 1994) and by us (Snyder, 1996). DeSalles and Hobbs shot tape-wrapped melons using a Carcano rifle and jacketed ammunition. In 11 shots they saw no jet-effect. In 1996 we undertook the resolve the apparent discrepancy. We shot a variety of melons with two different guns (30.06 and Carcano) and both jacketed and soft-nosed hunting ammunition. The results were surprisingly simple: Hunting bullets produced a jet-effect. Jacketed bullets did not produce a jet-effect. . . .

In his explanation of the head snap, Posner employs, in addition to the jet-effect, a so-called “neuromuscular spasm.” His full explanation might be described as jet-assisted neuromuscular spasm. Posner writes, “First, when the bullet destroyed the President’s cortex, it caused a neuromuscular spasm, which sent a massive discharge of neurological impulses from the injured brain down the spine to every muscle in the body.”

The authority for this statement is the House Select Committee on Assassinations forensic pathology panel. The HSCA is not as definite as Posner: “The panel further recognizes the possibility of the body stiffening, with an upward and backward lunge, which might have resulted from a massive downward rush of neurologic stimuli to all efferent nerves” (HSCA, 1979, 174-175).

The HSCA also suggested that “decerebrate rigidity” or DR as described by Sherrington (1898) “could contribute to the President’s backward motion.” No practicing neurologist or neuro-scientist testified that DR or a “massive downward rush of neurologic stimuli” could explain the head snap. DR is due to the absence of nerve signals that keep opposed muscles in equilibrium rather than “a massive discharge of neurologic impulses.” Since JFK is positioned facing to the left at the moment of the fatal head shot, any “upward and backward lunge,” whatever its cause, would have pushed JFK to the right, not the left.

The HSCA also noticed that “such decerebrate rigidity as Sherrington described usually does not commence for several minutes after separation of the upper brain centers from the brain stem and spinal cord,” but included DR in their stew of possibilities anyway (HSCA, Vol. 7, 174). (“Case Open: Skepticism and the Assassination of JFK,” Skeptic, volume 6, number 4, 1998, pp. 52-54. NOTE: I was unable to duplicate some of the math symbols, so I used to closest approximation that my keyboard offered.)

[Joe Elliott]

Below is one of Dr. Art Snyder’s critiques of the jet-effect and neuromuscular-reaction theories. Dr. Snyder is a former physicist at Stanford University. He received his PhD in physics from the University of Illinois. He taught physics at Indiana University before joining the staff at Stanford University. Dr. Snyder wrote this critique in 1998 in response to Gerald Posner’s arguments about JFK’s head snap in Case Closed:

. . .
The measurements of Itek and Thompson are almost inconsistent with a shot from a Mannlicher-Carcano. The motion is so large that nearly all the momentum of the bullet is needed to account for it. However, quantitatively Thompson and Itek were mistaken. The apparent motion between Zapruder frames Z312 and Z313 is an artifact of the blurring of frame Z313. This is not to say that JFK’s head did not move forward between frames Z312 and Z313, but that the Z313 blur obscures the motion so that it cannot be measured using these frames. The actual forward motion (~0.3 meter/sec) can be estimated by comparing Z313 to Z314. It is about 1/3 the value obtained using the Itek or Thompson measurements—consistent with a Carcano bullet imparting ~1/3 its momentum and ~1/2 its energy.
. . .

Dr. Snyder’s analysis is illogical. He claims that frame z313 is too blurry to get an accurate measure of how much the head moved forward between z312 and the blurry z313. Dr. Snyder’s solution? Compare the blurry z313 with z314.

If I may help out the confused Dr. Snyder, I think he meant to say that one should compare the non-blurry z312 with the non-blurry z314. I don’t know if this is necessary, but at least it’s a logical idea.


In addition, Dr. Snyder is just flat wrong that the WCC/MC bullet needs nearly all its momentum to push the head the amount reported by Itek.

I found some estimates of the mass of the human head as being 8 pounds, about 4 kilograms. I decided to make my own estimates. And I am sorry to report to the CTers of this forum that I did not do this by cutting my own head off but by measuring the circumference of my head. Both horizontally and vertically (over the top and under the chin). Assuming the same density of water (perhaps the density of bone is balanced by the sinuses) I came up with an estimate of 4.6 kilograms.

Doing some calculations, I find that moving a 4.6-kilogram mass forward with the momentum of a WCC/MC bullet going 1900 f/s, gives a calculated velocity of 1.3 meters per second. The observed Itek motion (which I recall was 2.1 inches) was 0.98 meters per second. So only about 75% of the momentum is needed, according to these calculations.

Further, there is no need to assume the entire head moved forward 2.1 inches. More likely, the head rotated forward, with the upper part of the head moving forward about 2.1 inches, and the lower part less.

All and all, by a rough estimate, only about half the momentum of the bullet is needed to move the head the observed amount in 55 milliseconds. This is inline with Ballistic Expert Larry SPersonivan’s estimate.

In actual truth, a WCC/MC bullet does have enough momentum to move JFK’s head forward about 2 inches in 55 milliseconds and still have enough momentum for its fragments to crack the windshield, dent the windshield frame, and slightly wound Mr. Tague. It is curious that the calculations are consistent with this hypothesis, as if this is exactly what happened.


By the way, my estimates and calculations:

•   Rough circumference of the head 60 to 70 cm, call it 65 cm.
•   Using the calculations for a sphere, volume of the head 4,600 cubic centimeters
•   Mass of the head 4.6 kilograms
•   Mass of the bullet 161 grains or 10.4 grams
•   Velocity of the bullet, 1900 f/s or 579 meters per second
•   Calculated velocity of the head after having 100% of the bullet’s momentum transferred, 1.31 meters per second
•   Observed velocity of the head in the Itek study, a movement of 2.1 inches in 55 milliseconds, or 0.98 meters per second

And this does not account for the head nodding forward, and not having the entire head move a full 2.1 inches forward.


And by the way, I would expect a real professional physicist to provide the basis of his calculations, as I did (a former high school physics student), like the estimated mass of the head, mass of the bullet, velocity of the bullet, calculated velocity of the head and the observed velocity of the head, and not just state “almost all the momentum is required”, with no numbers to back him up. Perhaps Dr. Snyder was having an off day.

[Michael T. Griffith]

From what I’ve seen, the WC apologists who post in this forum will never admit the validity of any fact or conclusion that refutes the lone-gunman theory, even if the evidence for that fact or conclusion is clear and compelling.

The 6.5 mm object on the autopsy AP skull x-ray is a good example of this refusal to acknowledge a fact and the conclusions that the fact clearly demands.

Obviously, the 6.5 mm object was planted on the AP x-ray after the autopsy in order to make it seem as though a 6.5 mm fragment had been deposited on the outer table of the skull, and in order to pad the case against Oswald, since Oswald allegedly used 6.5 mm ammo.

Scientifically, this is the only explanation that makes sense. We know from optical density measurements performed independently by three medical doctors that the 6.5 mm object is not metallic but that it is a ghosted image that was placed over the image of a small authentic fragment on the outer table of the skull at the rear of the skull. Dr. David Mantik, a radiation oncologist with a PhD in physics, has demonstrated how the object could have been placed on the AP x-ray using technology that was available at the time of the autopsy.

We also now know that the autopsy doctors each separately insisted to the ARRB that they did not see the 6.5 mm object on the night of the autopsy. They studied the x-rays carefully during the autopsy, since they were trying to find bullet fragments and recover them from the skull. The radiologist at the autopsy, Dr. John Ebersole, and the x-ray technician, Jerrol Custer, did not see the 6.5 mm object either.

The fact that the 6.5 mm object is not metallic is made especially clear by the fact that in order to have come from the alleged fatal head bullet, it would have to be from the cross-section of a full-metal-jacketed (FMJ) bullet, since the nose and tail of that bullet were supposedly found in the limousine. Forensic science knows of no case where an FMJ bullet has behaved in this manner. This fact is what led former HSCA ballistics expert Larry SPersonivan to conclude that the 6.5 mm object absolutely could not be a bullet fragment.

Forensic radiologist Dr. John Fitzpatrick examined the JFK autopsy skull x-rays for the ARRB. Dr. Fitzpatrick began his examination firmly believing that the autopsy materials were authentic and confident that he would prove them to be such. He was aware that some ARRB staff members believed that some of the autopsy materials had been altered. When he was given summaries of the research of Dr. Mantik and Dr. Robertson, he said he rejected their findings—even Dr. Mantik’s optical density measurements—because Mantik and Robertson were not forensic radiologists.

However, when Dr. Fitzpatrick examined the skull x-rays, he was profoundly disturbed by the 6.5 mm object. In fact, he extended his examination by an extra day just to study the 6.5 mm object further. He could never bring himself to call the object fake, but he observed that there was no corresponding object on the lateral skull x-rays:

No object directly and clearly corresponding to the bright, 6.5 mm wide radio-opaque object in the A-P X-Ray could be identified by the consultant on the lateral skull X-Rays. Although there is a mere trace of some additional density near the fragment bilocation at the vertex of the skull, the consultant did not feel this object was anywhere near the density/brightness required for it to correspond to the bright, radio-opaque object on the A-P X-Ray. After briefly speculating that the small metallic density behind the right eye in the lateral X-Rays might correspond to the bright radio-opaque density in the A-P X-Ray, this idea was abandoned because neither the locations nor the density/brightness of the 2 objects are consistent. (Meeting Report, ARRB, 2/29/96, Independent Review of JFK Autopsy X-Rays and Photographs By Outside Consultant-Forensic Radiologist, p. 2, https://www.maryferrell.org/showDoc.html?docId=145280&relPageId=225)

When Dr. Fitzpatrick met with ARRB staffers the day after he finished his examination of the autopsy x-rays, he remained troubled by the 6.5 mm object. He said the object “almost” looked like it had been “machined off” or “cut off” a bullet. He even floated the implausible speculation that the fragment had dropped off the skull before the lateral skull x-rays were made:

The following day, February 7, 1996, Dr. Fitzpatrick met with ARRB staff. . . .

He continued to be disturbed and puzzled by the fact that the large radio-opaque object in the A-P skull X-Ray could not be located on the lateral skull X-Rays. At one point he speculated that perhaps this fragment fell off of the President’s body before the lateral X-Rays were taken. He opined that the 6.5 mm radio-opaque object in the A-P skull X-Ray looked “almost as if it had been machined off, or cut off of a bullet.” (Meeting Report, ARRB, 2/29/96, p. 4)

Since Dr. Fitzpatrick was ardently determined not to even allow for the possibility that the autopsy x-rays had been altered, he never resolved the conflict between the AP and lateral x-rays regarding the 6.5 mm object. He never ventured to put in writing an explanation for why the 6.5 mm object does not appear on the lateral x-rays, which it would do if it were a bullet fragment. Nor did Dr. Fitzpatrick make any attempt to explain Dr. Mantik’s multiple sets of optical density measurements of the 6. 5 mm object, even though he was made aware of them and was also advised that Dr. Mantik held a PhD in physics. But he should be given credit for at least being willing to identify this striking conflict in the autopsy evidence.

Dr. Fitzpatrick's refusal to acknowledge that the 6.5 mm object is fake and cannot be a bullet fragment is a good example of what happens when you believe something so ardently, so passionately that you cannot abandon that belief even when you stare straight at clear, hard physical evidence that your belief is wrong.

[Joe Elliott]

From what I’ve seen, the WC apologists who post in this forum will never admit the validity of any fact or conclusion that refutes the lone-gunman theory, even if the evidence for that fact or conclusion is clear and compelling.

The 6.5 mm object on the autopsy AP skull x-ray is a good example of this refusal to acknowledge a fact and the conclusions that the fact clearly demands.

Obviously, the 6.5 mm object was planted on the AP x-ray after the autopsy in order to make it seem as though a 6.5 mm fragment had been deposited on the outer table of the skull, and in order to pad the case against Oswald, since Oswald allegedly used 6.5 mm ammo.

No, this is not obvious or compelling.

The object does not look like a bullet fragment. Why would conspirators plant evidence that does not look like a bullet fragment?

They make it look like the bullet passed all the way through the head. There is an entrance would and an exit wound (well really an explosive wound). They plant fragments in the car that make it appear the fragments exited the head. They damage the windshield frame and the windshield, to make it look list the fragments not only left the head but did so at great speed.

And then they decided to plant a fake fragment that doesn’t even look like a fragment? Why do this? Why would some fragments exit the head at great speed, dent the frame, crack the windshield and possibly wound Mr. Tague, while another sizeable fragment stays behind in the head? Why would the conspirators think that this would be a good idea?

And only do this for one X-Ray but not the others, to make it look like the ‘fragment’ magically disappeared? Why would they do this?


None of this makes sense. What does make sense? An object fell onto the head. Maybe out of someone’s pocket. They took an X-Ray without noticing the object. Before the next X-Ray, someone spotted the object and removed it. They knew it didn’t belong there. That is why this “object” only appears in one X-Ray. What was this object? It is impossible to tell from the X-Ray.

Is this really true? Impossible to say, but at least, this is a sensible hypothesis.


If this is evidence of a planted object in the head, or doctoring just one of the X-Rays, this doesn’t make sense. Did the conspirators plant the object, take an X-Ray, figured that is good enough and remove the object and took the rest of the X-Rays? Or did they ‘doctor’ one X-Ray, figured that was good enough, and didn’t bother doctoring the other X-Rays to be consistent?

None of this makes any sense, let along provides “compelling evidence”.

[Joe Elliott]

Planting a “6.5 mm” circular object to appear in an X-Ray does not make sense for the following reasons:

1.   First, it should be noted that one cannot reliably measure the size of an object in an X-Ray. The closer the object is to the source of the X-Rays, the larger it will appear. We really don’t know if the object really had a diameter of “6.5 mm”, or under 6 mm, or over 7 mm. Its apparent size is affected by whether it was resting on the outside on the near side of the head, or the far side, or somewhere in the middle.

2.   Second, planting such an object does not implicate Oswald. Lots of bullets are of that size. It is impossible to use an X-Ray of a bullet to identify it being fired from Oswald’s rifle, to the exclusion of all other rifles in the world, or even to identify it as a WCC/MC bullet, particularly when viewed “Lengthwise’.

3.   No need to implicate Oswald in this way, since as I recall one or both of the recovered large fragments from the head shot, and certainly CE-399, provided the evidence that they were fired from Oswald’s rifle, to the exclusion of all other rifles in the world. X-Rays are never used to prove this.

4.   The evidence shows, or were made to show, that at least two and probably three large fragments exited the head at a high speed. As evident from the large dent in the windshield frame and crack in the windshield. Why would a fourth large fragment remain in the skull? Does it make sense that the head would slow some large fragments by 950 feet per second and others by 1900 feet per second? Tiny fragments can be stopped by the head. They have a large surface area relative to mass. But large fragments? A quarter of an inch across? Why would the ‘fakers’ think that some large fragments would be stopped in the head while others wouldn’t and would exit at great speed.

5.   Why only have the fake evidence show up in only one X-Ray? Did they put the object in the head, take an X-Ray, figured that was good enough, remove it, and then take the rest of the X-Rays? Doctor one X-Ray, figured that was good enough and left the rest alone?

6.   Why plant an object that doesn’t look like a fragment of a bullet? A bullet would only look like that if it was not damaged, remained totally intact, stayed in the skull, and just happened to be X-Rayed lengthwise. But the other evidence, the presence of both entrance and exit wounds, the damage to the limousine’s windshield frame and windshield, show that didn’t happen.


Some other explanation must be true. People carry all sorts of objects in their pockets. Objects about a quarter of an inch across, and disk shaped, are pretty common. Would a breath mint show up? An Antacid? An Antacid commonly contains calcium, doesn’t it? That should show up in an X-Ray, I would think. Aspirin tablets are commonly that size. And pills, in general, or often disk shape to make them easy to shallow. Just a few possibilities. While moving and positioning the body for the X-Rays, something unnoticed might fall out and get X-Rayed. The technicians may then spot it, remove it and continue with their work. They might believe that the object would not shown in an X-Ray. In any case they needed to move things along so the Kennedy family can be allowed to leave with the body.

Speculation? Yes. As is speculating conspirators planted an object that makes no sense.

[Michael T. Griffith]

Another fact that should be mentioned is that all of the Parkland doctors’ treatment reports, written on the day of the assassination, described the large wound as being in the back of the head, using the terms “posterior,” “occipital,” and “occipital-parietal” to describe its location. Significantly, the treatment reports also state that there was considerable damage to the cerebellum and cerebellar tissue missing. This is crucial for two reasons: One, cerebellar tissue is located only in the back of the head, on the lower half of the back of the head. Two, cerebellar tissue is easily distinguished from other brain tissue.

In his video Altered History: Exposing Deceit and Deception in the JFK Assassination Medical Evidence, Doug Horne, former chief analyst of military records for the ARRB, presents the wound diagrams drawn for the HSCA and the ARRB by medical personnel and federal agents who got good, close, prolonged looks at JFK’s large head wound.

Horne also discusses the fact that two federal agents (Sibert and O’Neill) disputed the accuracy of autopsy photo F3, which shows the back of the head intact, when interviewed by the ARRB, and that Dr. John Ebersole also challenged the accuracy of the photo when interviewed by the HSCA. The fact that Ebersole challenged the photo was not known until the ARRB released the HSCA interview reports. Horne discusses the fact that in 2006 we learned that Dr. Robert O. Canada, who was the commanding officer of the treatment hospital at Bethesda Naval Hospital and who witnessed the autopsy, told historian Michael Kurtz that he saw a “very large, 3-5 cm wound in the right rear of the President’s head, in the lower right occipital region,” and that the wound was “clearly an exit wound.” Additionally, Horne reviews the evidence about the Harper fragment.

The discussion about these items and much more begins at 49:55 (the discussion runs about 20 minutes):

https://www.fff.org/explore-freedom/article/altered-history-exposing-deciet-and-deception-in-the-jfk-assassination-medical-evidence-part-1/

In Part 3, Horne presents an in-depth look at the scientific evidence that the autopsy x-rays and brain photos have been altered. By the way, Dr. Mantik took optical density measurements of the skull x-rays because those measurements are a key tool in radiation oncology, which is Dr. Mantik's field of specialization (he's a radiation oncologist). Horne's presentation of the scientific evidence is especially good because he explains the more technical points in layman's terms so that the average person can understand the evidence and can grasp just how powerful the evidence is. He also explains how the x-rays were altered.

https://www.fff.org/explore-freedom/article/altered-history-exposing-deceit-and-deception-in-the-jfk-assassination-medical-evidence-part-3/

[Michael T. Griffith]

Dr. Snyder’s analysis is illogical. He claims that frame z313 is too blurry to get an accurate measure of how much the head moved forward between z312 and the blurry z313. Dr. Snyder’s solution? Compare the blurry z313 with z314.

If I may help out the confused Dr. Snyder, I think he meant to say that one should compare the non-blurry z312 with the non-blurry z314. I don’t know if this is necessary, but at least it’s a logical idea.

In addition, Dr. Snyder is just flat wrong that the WCC/MC bullet needs nearly all its momentum to push the head the amount reported by Itek.

I found some estimates of the mass of the human head as being 8 pounds, about 4 kilograms. I decided to make my own estimates. And I am sorry to report to the CTers of this forum that I did not do this by cutting my own head off but by measuring the circumference of my head. Both horizontally and vertically (over the top and under the chin). Assuming the same density of water (perhaps the density of bone is balanced by the sinuses) I came up with an estimate of 4.6 kilograms.

Doing some calculations, I find that moving a 4.6-kilogram mass forward with the momentum of a WCC/MC bullet going 1900 f/s, gives a calculated velocity of 1.3 meters per second. The observed Itek motion (which I recall was 2.1 inches) was 0.98 meters per second. So only about 75% of the momentum is needed, according to these calculations.

Further, there is no need to assume the entire head moved forward 2.1 inches. More likely, the head rotated forward, with the upper part of the head moving forward about 2.1 inches, and the lower part less.

All and all, by a rough estimate, only about half the momentum of the bullet is needed to move the head the observed amount in 55 milliseconds. This is inline with Ballistic Expert Larry SPersonivan’s estimate.

In actual truth, a WCC/MC bullet does have enough momentum to move JFK’s head forward about 2 inches in 55 milliseconds and still have enough momentum for its fragments to crack the windshield, dent the windshield frame, and slightly wound Mr. Tague. It is curious that the calculations are consistent with this hypothesis, as if this is exactly what happened.

By the way, my estimates and calculations:

•   Rough circumference of the head 60 to 70 cm, call it 65 cm.
•   Using the calculations for a sphere, volume of the head 4,600 cubic centimeters
•   Mass of the head 4.6 kilograms
•   Mass of the bullet 161 grains or 10.4 grams
•   Velocity of the bullet, 1900 f/s or 579 meters per second
•   Calculated velocity of the head after having 100% of the bullet’s momentum transferred, 1.31 meters per second
•   Observed velocity of the head in the Itek study, a movement of 2.1 inches in 55 milliseconds, or 0.98 meters per second

And this does not account for the head nodding forward, and not having the entire head move a full 2.1 inches forward.

And by the way, I would expect a real professional physicist to provide the basis of his calculations, as I did (a former high school physics student), like the estimated mass of the head, mass of the bullet, velocity of the bullet, calculated velocity of the head and the observed velocity of the head, and not just state “almost all the momentum is required”, with no numbers to back him up. Perhaps Dr. Snyder was having an off day.

Or perhaps all of your irrelevant, diversionary nitpicking does not lay a finger on any of Dr. Snyder's points. You really show yourself to be a blind, diehard, unreachable partisan when you stoop to questioning the competence of recognized, genuine scientists just because they don't buy the lone-gunman theory.

I notice you said nothing about the ballistics tests that he and Dr. DeSalles did, both of which showed that jacketed ammo does not produce a jet effect.

I notice you said nothing about the fact that good ole Dr. Lattimer claimed that in his ballistics test, the target objects were propelled toward the gun every single time, a result that nobody has ever seen or claimed to have seen in any other test.

I notice you said nothing about Dr. Snyder's points regarding the neuromuscular-reaction theory, such as his point, which other scholars have also made, that "since JFK is positioned facing to the left at the moment of the fatal head shot, any 'upward and backward lunge,' whatever its cause, would have pushed JFK to the right, not the left."

And I notice you said nothing about Dr. Snyder's point that after spending many paragraphs trying to prove that the motion of the head tells us nothing about the direction the bullet was traveling, Posner spins around and argues that the forward motion of the skull indicates a shot from the rear.

I should mention that Dr. Snyder did say that he was comparing Z312 to Z314. I mistyped 312 as 313. I've corrected this in the post.



And now to some of your comments about the 6.5 mm object:[/size]

Some other explanation must be true. People carry all sorts of objects in their pockets.

Yes, yes, there just "must" be some other explanation, instead of the obvious, scientifically demonstrated one.

Objects about a quarter of an inch across, and disk shaped, are pretty common. Would a breath mint show up? An Antacid? An Antacid commonly contains calcium, doesn’t it? That should show up in an X-Ray, I would think. Aspirin tablets are commonly that size. And pills, in general, or often disk shape to make them easy to shallow. Just a few possibilities. While moving and positioning the body for the X-Rays, something unnoticed might fall out and get X-Rayed. The technicians may then spot it, remove it and continue with their work. They might believe that the object would not shown in an X-Ray. In any case they needed to move things along so the Kennedy family can be allowed to leave with the body.

LOL!  So it has come to this?!  You are reduced to theorizing that Humes, Boswell, or Ebersole, for some reason, was holding an antacid or breath mint tablet during this part of the autopsy and accidentally dropped it under JFK's head, without anyone noticing, before the AP x-ray was taken!  Or, that someone else somehow dropped a pill under JFK's head and nobody noticed it!  And by amazing coincidence, the pill/tablet just happened to be 6.5 mm wide and thus became the largest "fragment" in the skull x-rays!!!  Yet, somehow, this pill or tablet appears only as a tiny fragment on the lateral skull x-rays!!!  This is the kind of silliness you must employ when you won't allow yourself to reach the obvious, logical, scientifically documented conclusion.

Let us review some facts about the scientific evidence of alteration in the autopsy skull x-rays:

* The 6.5 mm object is impossible to miss on the AP x-ray. It is the largest and brightest object on the x-ray. In fact, it is even brighter than JFK's fillings. That means it should be the densest "fragment," denser than the metallic fillings in JFK's death, but it is not. Think about that.

* The 6.5 mm object has no density itself, even though it is brighter than the dental fillings. Its only actual density comes from the small genuine fragment over which it was placed. So the object cannot be a pill or tablet or any other physical object. It is a ghosted image.  Three medical doctors with expertise in radiology have confirmed this fact with optical density (OD) measurements and via direct analysis of the object. It first occurred to Dr. Mantik to measure the object in this way because he uses OD measurements frequently in his work as a radiation oncologist.

* Dr. Mantik did OD measurements on comparison x-rays with genuine cross-sections from 6.5 mm bullets to act as control measurements for the OD measurements of the 6.5 mm object. The two sets of OD measurements are drastically different.

* Dr. Mantik found that with only modest magnification, one can clearly see the small genuine fragment inside/through the 6.5 mm object, precisely because the object is a ghosted image.

* The images of the 6.5 mm object are spatially compatible on the AP and lateral x-rays, even though the object is far larger and brighter on the AP view, which rules out the idea that the object is some kind of accidental artifact.

* The strange bright patch on the right-rear part of the head in the two lateral skull x-rays transmits 1,100 times more light than does the frontal region of the skull, which is a physical impossibility for a genuine x-ray. On a normal x-ray, the brightest part of the white region would only transmit 2-3 times more light than the frontal region. Even on other parts of the skull, on a normal x-ray the brightest area will be no more than 2-3 times brighter than the darkest area.

* OD measurements done on the same regions on undisputed JFK x-rays made in 1960 are wildly different from the OD measurements done on the lateral autopsy skull x-rays, which is a physical impossibility unless the autopsy x-rays have been altered. As Dr. Chesser notes,

In the lower occipital-temporal area a fracture terminates when it runs into the “white patch,” an area of the skull which appears impossibly dense compared to the same region on the skull x-ray taken in 1960. (https://kennedysandking.com/images/pdf/michael-chesser-houston-2017.pdf)