The Fatal Shot: Was President Kennedy Hit From The Front?

A critical reexamination of the Zapruder film

Bernard Oattes
Bolestein 292
1081 EC Amsterdam, Holland
March 1993

(Mr. Oattes invites comments at

   The infamous 'head snap' sequence in the Zapruder film has often been referred to as visible proof of a bullet hit from the grassy knoll area. Without referring to precisely quantified measurements, I will argue that whatever its causes, the backward movement of President Kennedy's upper body was not caused by a bullet hitting him from the front.
    The Zapruder film itself provides strong support for this notion, even on an 'eyeball' basis. An attempt will be made to offer an alternative explanation for the backward movement, and other evidence that appears to support the grassy knoll hit theory will be critically evaluated.

Interpreting The Headshot Sequence
The problem with using the Zapruder film as evidence of any kind of gunfire from the front is that it must clearly show either the gunman shooting or physical evidence of impact and/or resulting damage on Kennedy's body, in a location consistent with the position of such a gunman. The crucial question is: does the film show any of these elements? When we examine the headshot sequence closely, we see the following:

1.      Comparison between frames 312 (preimpact) and frame 313 (postimpact) reveals a forward movement of the head and shoulders.

2.      Massive damage is seen to be inflicted on the head in frame 313, as brain tissue, blood and bone fragments are propelled forward and upward.

3.      Subsequent frames show a wound in the top right side of the head. A piece of skull bone is still attached to the scalp, hanging down the right side of Kennedy's face, just in front of his right ear, covering the area of his right temple. This head wound can be clearly seen not to extend behind the (imaginary) line that connects both ears across the top of the head. Immediately before Jackie Kennedy gets up, the wound is visible as an interruption in the outline of the skull: a large section of the right half of the top of his head is missing, leaving an almost fist-sized defect. As far as the back of the head is concerned: nothing is visible at any time during the headshot sequence that would indicate that the back of the head is not intact.

4.      A marked backward motion of the head and upper body followed by Kennedy slumping further to the left and downward.

      A coherent pattern is discernible here: the forward motion of the head and shoulders, the direction and velocity of the brain tissue and blood spraying outward, the latter's simultaneous occurrence with the move forward, as well as the location and obvious exit nature of the resulting head wound. How likely is it that the force causing all these phenomena did not come from behind President Kennedy?  The fourth element, namely the backward upper body movement appears unconnected to the pattern that the first three obviously form.
Before we deal with this backward movement, let us ask the following question: what could we expect the Zapruder film to show if Kennedy was indeed hit in the head from the right front?
The elements most likely to be seen would be:

        A marked movement of head and upper body to the left and backwards, the head pivoting in the neck area in relation to the torso. A bullet striking the top of the head would cause it to snap backwards and most probably to the left side, driving the chin up , accompanied almost immediately by the upper body traveling in the same direction.

        Brain tissue, blood and / or bone fragments being blown out of the back of the head.

        A wound of exit remaining at the back of the head. Consistent with the position of a grassy knoll gun, this exit wound would not be at the right of the back of the head, but more towards the middle / left part, i.e. somewhere behind the left ear.

      Given the location of the grassy knoll in relation to the respective positions of Kennedy and Zapruder at the time of frame 313 and immediately afterwards, we can safely assume some sign of impact and / or exit would become visible. As for a remaining defect, the back of the head can be seen after frame 313 until Kennedy slumps out of view.
Turning once again to our analysis of the Zapruder film, we cannot help but notice that such a pattern of impact, accompanied by physical change taking place and a changed state resulting, is dramatically absent. How likely is it that of all the elements of the pattern we could expect to see, a bullet hit from the front would cause only the most ambiguous one, namely the backward movement of the head? Only if a bullet entered but did not exit would this be possible, thus changing our question into: how likely is it that a bullet fired from the grassy knoll area entered Kennedy's head but did not exit? Our analysis shows that a bullet hit from behind is extremely likely, which would bring us into a 'double hit' theory.
The Zapruder film shows unambiguously that the first change is a pivoting motion of Kennedy's head to the front and downward, accompanied by immediate massive damage to the head. Certain particles are seen to be several feet away from the head in the very first frame that shows any change at all, Z 313. This implies that the exit wound was very probably already in existence by the time the alleged second bullet arrived.
Where did this second bullet enter? All the known evidence suggests there was no entry wound anywhere on the right side of Kennedy's head. Therefore, if it did enter, it would seem likely that the location of entry was somewhere within or very close to the outline of the exit wound caused by the bullet from behind. Thus the bullet's entry into the brain would be either completely unobstructed by skull bone, or, at worst, only partially, by structurally weak bone at the perimeter of the large defect already in existence.
Without encountering much or possibly any resistance from skull bone when entering, both the velocity and shape of the alleged second bullet would be such that it could reasonably be expected to exit, or at the very least cause visible damage to the back of the head. The bullet from behind traveled the distance from some sniper's nest to Kennedy's head, broke through the skull when entering, but still had enough momentum to cause an almost fist-sized exit wound. How could a bullet fired from much closer, while encountering significantly less resistance, fail to do at least half that structural damage?
As for the notion that a dum-dum bullet was used, which would have exploded on impact, a problem arises regarding the entry in the skull. If, as would appear likely, this bullet could enter the brain with little or no resistance from bony matter, the first real impact would have been against the inside of the back of the skull, as it was about to exit. We should have seen some sign of change at that point. In addition, especially if the bullet did not exit in spite of the fact that the first real resistance it encountered was the skull from the inside, we would expect to see a marked pivoting of the head to the left and backwards in relation to the upper body. However, the angle the head makes in relation to the torso shows no significant change except the forward movement in Z 313. Surely some kind of visible effect would have resulted there. So, we are left only with the movement backwards to prove a theory of frontal entry.
But even this phenomenon in itself presents serious problems. Strikingly, the sudden reversal of direction of movement we see in the comparison of Z 313 with Z 314 and onwards is a reversal for both head and torso. When arguing that this motion reversal is caused by the force of a bullet, slamming the President backwards and to the left, the question immediately arises as to why the head does not pivot backwards first, driving the chin away from the chest, only then to be followed by the torso. Especially if the bullet did not exit, the energy that would have gone into the structural damaging of bony matter would be turned into movement, i.e., a kinetic reaction changing the head's angle with the upper body. In the analysis of what is often called the 'head snap', it is especially disturbing that there is, in fact, no real head snap at all.
There is even more evidence in the Zapruder film that strongly indicates the improbability of the frontal bullet hit thesis.
Quite apart from issues of wound visibility, let us consider Kennedy's position relative to the location where the available evidence would place a grassy knoll gunman, at the time of the fatal shot. If we imagine the face of a clock, laid out horizontally with President Kennedy in the center, facing 12 o'clock, we can see that the gunman would be located approximately in his 2 o'clock position, i.e. two-thirds of the way along from his front (12 o'clock) to his right (3 o'clock). A bullet hit from there would drive his head and upper body towards the 8 o'clock position, i.e. in a direction with a leftward component of 66% and a backward component of 33%. The Zapruder film however, shows Kennedy slumping and sliding to his left and down only after he has fallen backwards in a direction from which this necessary left lateral component is virtually absent. In other words, a bullet hitting the body from a relative location at 2 o'clock should drive it in an 8 o'clock direction ; the Zapruder film shows movement first in the 6 o'clock direction (a difference of some 60 degrees!), followed by a gradual sliding away towards 9 o'clock. This is a major inconsistency, undercutting the argument that a bullet struck President Kennedy from the grassy knoll; even if the gunman was positioned more towards the triple underpass, the angles would not match.
We have established the very strong probability that an exit wound and / or the events of entry or exit, related to a hit from the right front would become visible at some point after frame 313, and that Kennedy's head and upper body would initially move more to the left than backward.
The following conclusion is now warranted:
By lacking any trace of a coherent pattern of visible effects related to a bullet striking Kennedy in the head from the right front, the Zapruder film disqualifies any theory incorporating such a notion.
Although the Zapruder film itself is sufficient ground for reaching this conclusion, the fact that no exit wound in the left rear of the head was ever reported by any witness or critic, as well as the absence of such a wound in the autopsy photos, provide massive support for it.

A Possible Explanation Of The Backward Motion
The validity of the above conclusion is not contingent upon the presentation of an adequate causal explanation of the backward motion of the President Kennedy's head. Nevertheless, we will examine a number of possible influences that may have contributed towards it. As such, they do not form a complete or coherent theory of the backward movement, but their importance, especially in combination, may well have been overlooked.
Let us examine Kennedy's specific physical posture at the time of the headshot. Seconds before Z 313, he can be seen sitting semi erect, upper body and arms not supported by either the backseat or other parts of the car, his head bent downwards. He is leaning over to his left slightly, legs in front of him. The center of gravity of the unsupported part of his body is behind and slightly to the left of where it touches the seat. This implies the following:

1.      The body is predisposed to fall in that direction, i.e. backward and somewhat to the left, simply because it would encounter the least resistance that way. Muscle power is a major factor in keeping it from falling in that direction.

2.      The head is inclined downward, with the chin close to the chest. Tendons and muscles of the neck and upper back are stretched out to a larger degree than they would be if a person were sitting up straight.

3.      Kennedy was wearing a back brace. Based on descriptions by doctors Carrico and Akin, as well as secret service agent Greer, we can infer with reasonable certainty that it would have impaired the President's ability to bend his upper body. This bending in relation to the hips as well as curving of the lower spine are the very kinds of movement the back brace is designed to restrict.

      With these factors in mind, let us consider the following scenario. The bullet strikes the back of the head, losing most of its momentum by causing structural damage to the head and to itself. It also causes forward movement of the head. The head pivots down in relation to the torso. Tendons and muscles of the neck and upper back are stretched for one instant to the limit of their capacity. The head springs back up as a reaction to this overstretching. In the meantime the torso's forward movement has been arrested by the back brace. Muscular power holding the body up is interrupted by the sudden massive brain damage, and it will slump and fall in the direction of least resistance, i.e., to the rear and slightly to the left. The impetus given by the head springing back up after the impact, acts together with this falling towards the center of gravity. After the energy from this initial sharp jolt upwards has dissipated, the lack of muscular power allows the body to fall towards the rear seat. The body hits the rear seat and slides slowly to the left.
The debate about the possible influences of the 'jet effect', the neuromuscular spasm and an inadvertent transfer of motion by Jackie Kennedy falls outside the scope of this discussion. Suffice it to say that what has been described above does not preclude any of the implications of these possible effects. In fact, the above scenario may well be a factually correct description of a large part of the causal factors involved in the backward head movement, with others, such as the 'jet effect', also contributing towards it.
The following additional observation regarding the perceived speed of the movement is important. Frames 318 and 319, in the middle of the backward movement of upper body and head, are smeared as a result of camera movement. The direction of the smear coincides with that of the movement of the President's body, thus enhancing the impression of rapid backward movement. This effect is neutralized with more careful measurement as was done by ITEK and by Thompson, but when viewing the sequence real time, it can be confusing. Maybe this is why so many who have seen it get the impression of great speed and force. The Zapruder film itself however, proves that this is not the case. As the back touches the rear seat, we can observe that the force involved is not even great enough to throw the head backwards, driving the chin up and away from the chest, as a result of the back being unable to move any further, thus transferring momentum to the unobstructed head. Similarly, if the sudden acceleration backward was caused by a bullet hit in the head, why isn't the head driven up and backwards before the torso? The resistance against such a pivoting motion could not possibly have been greater than the impact force of a bullet, especially if it did not exit. These could be strong indications that the velocity of the backward movement after Z 313 may well have been overestimated all along.
The acceleration measurements presented in Thompson's Six Seconds in Dallas are described by himself as having been done "in a rough way" in 1967. Whatever method could be used today, the fact remains that the degree of precision will always be adversely affected by the relatively long interval of one-eighteenth of a second between frames.

Remaining Questions
Many questions can still be raised concerning the head movement that has mystified experts and laymen alike. Some of the more well-known issues will be addressed here.

        The most important body of testimony at variance with the Zapruder film was that of the majority of the Dallas doctors. In most of their accounts, the wound is further to the back, extending into the right occipital area, behind the right ear. This is seen as evidence for frontal entry of a bullet. This location is however, inconsistent with the position of the grassy knoll in relation to the President at the time of the headshot. An exit wound resulting from a shot that came from a right front location would most likely be positioned not in the right rear but in the middle to left rear of the head.
      It is interesting in this context to note that apart from agents Kinney and Roberts, bystanders Newman and Sitzman, Patrolman Jacks, reporter Kantor and Zapruder himself, two Dallas doctors described the wound in essential agreement with the Zapruder film. The testimony of doctors Baxter and Jenkins did not concur fully with that of their colleagues. Baxter described the 'temporal parietal plate of bone' as missing, leaving a defect of some 8 to 10 centimeters in size, which is what the film shows. Dr. Jenkins described ' a great laceration on the right side of the head' and indicated the wound location and size seen in the Zapruder film. Nurse Nelson too indicated the head wound where the film shows it to be. In recent years, the original testimony of some of the Dallas doctors was changed. After viewing the autopsy photos on the 1988 NOVA program, they indicated that in essence, these showed what they had seen that afternoon in 1963. Whatever the reasons for this, it undercuts their original testimony's emphasis on a right occipital location. Some researchers regard the long period of time between original and changed testimony with suspicion. Whatever the reasons for it, the fact that the doctors in question should change their views at all, undercuts the strength of their 1963 testimony.
      Many ambiguities still remain concerning this issue.

        A number of witnesses have claimed they heard gunfire from the grassy knoll and saw a shot 'hit' the President in the head. In his testimony, Bill Newman for example clearly links the sound of a shot from behind him with the shocking visual evidence of a bullet suddenly wounding the head of President Kennedy. Mr. Newman cannot be blamed for mistaking an exit wound for evidence of impact on the head.

        Jackie Kennedy climbed out onto the back of the limousine after the headshot occurred. Many would have us believe she is reaching out for a piece of her husband's skull. There is no evidence whatsoever for the existence of this alleged piece of skull, and the Zapruder film does not show it. What the film does show quite unambiguously is that Jackie Kennedy does not look toward the back of the limousine until after she is already well out of her seat. So unless she had eyes on the right side of her head, she could not have seen what was or was not on the back of the limousine. It is much more likely that she is reacting in blind panic, repulsed by what she sees and perhaps instinctively trying to get away to keep from getting killed herself.

        Police officer Hargis reported being splattered by blood and debris from the head wound with some force. Given his location behind and to the left of the President, this is seen as evidence of a bullet hit from the grassy knoll. It is entirely conceivable however, that he drove into a cloud of such brain tissue, blood and bone splinters. Given the height to which frame 313 shows that some particles traveled, their direction would have required only a small left lateral component for them to have fallen back down into the path of the policeman in question. The horizontal speed of these particles, especially the smaller ones, relative to the ground, quickly decreased as they encountered air resistance, so that the speed of the motorcycle became an important factor in causing the force with which they struck Hargis.

The work of some critics is based on the notion that a grassy knoll gunman killed President Kennedy. The presence of such a smoking gun on the knoll has always been very important, as it was seen as the direct falsification of the Warren Report's assertion that Oswald did the shooting alone from the School Book Depository. The 'head snap' functioned as proof of conspiracy for many writers and laymen from the start.
It is very likely that there were other gunmen in Dealey Plaza, based on the testimony of witnesses present. The evidence of gunfire from the grassy knoll area is considerable. Many critics believe that photographic evidence has been faked in order to confuse us as to the origin of the shots. Robert Groden's insistence that the autopsy photo showing the back of Kennedy's head is false, is an example of this thinking.
Mr. Groden is considered an authority on the Zapruder film, yet the autopsy photo in question (HSCA F 48), that he claims is forged, shows a wound very similar in size and location to the one seen in frames Z 313 onwards. By claiming the photo is false, he must denounce the Zapruder film on the same grounds. He opted for claiming that the film does show 'the back of the head was missing' in his book High Treason, a bold and improbable assertion, but perhaps easier than proving the film is a forgery.
David Lifton's theory of wound alteration is grounded on the notion of frontal entry, and he has always considered the original testimony of the Dallas doctors, in which they describe an exit wound at the right rear of the head, as the most important evidence of a hit from the grassy knoll, i.e. conspiracy. He too is left with only one option, namely to prove that the film is a forgery.
Either both the medical and the photographic evidence were altered, or neither was.
Cyril Wecht's defense of the 'double hit' theory is based on the reasoning that the sudden movement of the head and upper body after frame 313 can only be explained by a bullet hit from the grassy knoll, driving Kennedy backwards and to the left. As we have seen, the direction of the movement backwards cannot be linked that easily to the position of the grassy knoll gun: there is a discrepancy of some 60 degrees. Hopefully, this paper has succeeded in presenting a more subtle and detailed description of the forces and circumstances in operation at the time.

      Although this paper in no way presents one comprehensive theory about the assassination, it will have served its purpose if the observations made here can aid further theory formation and, ultimately, bring us closer to what really happened in Dealey Plaza in 1963.
Faced with a secretive adversary, the critics should beware of misconceptions and leave dogmatism to their opponents.

I want to thank Paul Hoch and Josiah Thompson for their helpful comments.

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