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

[Chris Davidson]

Goats are passé.

[Dan O'meara]

PS  A little something for you and all the other "shot-from-the-front" CTers out there to bear in mind:

Back muscles are significantly stronger than stomach muscles.

Hmmm ...

What about neck muscles?

[Ted Shields]

What about neck muscles?

If all of the bodys muscles tense up, the back "wins" - ie the body will react like JFKs did.

The forward movement on impact makes a shot from the front impossible.

[Michael T. Griffith]

Sturdivan may have been using "decerebrate reaction" synonymously with "neuromuscular reaction" ,but you err in assuming that he was using "decerebrate rigidity" synonymously with "neuromuscular reaction". He used "terminus of the decerebrate reaction" synonymously with "decerebrate rigidity".

So you are still trying to salvage your misreading of Sturdivan’s testimony? Sad. I never said that Sturdivan used "decerebrate rigidity" as a synonym for "neuromuscular reaction." Go back and read my reply. Sturdivan was not a medical scientist of any kind. He made several mistakes when he talked about the medical aspects of Kennedy's movements. Part of the problem seems to be that you have not done enough research on the medical and ballistics evidence to understand what you are reading in some cases.

Here is some reading for you. This is Dr. Donald Thomas’s destruction of Sturdivan’s defense of the neuromusuclar-reaction theory. Dr. Thomas, a research scientist whose work has been published in peer-reviewed forensic journals, shows that Sturdivan got the anatomy wrong, got the muscle functions wrong, and got the medical science wrong, and that the goat film is irrelevant because of the enormous differences in goat and human anatomy and because the goat's movements do not duplicate Kennedy's movements. Dr. Thomas also explains why it would have been impossible—not just improbable or unlikely, but impossible--for a neurospasm to have caused Kennedy’s backward movement.

The panel [the HSCA’s forensic pathology panel] seems to have confounded different neuromuscular phenomena. . . .  The origin of this scenario is found in the testimony of an expert with the Army’s Edgewood Arsenal, Larry Sturdivan. Sturdivan proposed that because the muscles in the back of the arms and legs are much larger than the ones in the front, and because the muscles of the back are much larger than the abdominals, then stimulation of all the muscles would result in a backward motion.

Sturdivan’s postulate suffers from a patently anomalous notion of anatomy. In any normal person the antagonistic muscles of the lims are balanced, and regardless of the relative size of the muscles, the musculature is arranged to move the limbs upward, outward, and forward. Backward extension of the limbs is unnatural and awkward, certainly not reflexive. Likewise, the largest muscle in the back, the erector spinae, functions exactly as its name implies, keeping the spinal column straight and upright. Neither the erector spinae or any other muscles in the back are capable of causing a backward lunge of the body by their contraction. The reader is invited to sit on the edge of a bed and attempt to lunge backward by muscle contraction. Such a movement is unnatural, not reflexive, and can be achieved only by relaxing, not clenching, the muscles of the trunk. 

Sturdivan’s concept of muscular anatomy only begins to make sense when one realizes that his standard of reference must have been the goats used in the Army’s terminal ballistics experiments. The muscle arrangement in a quadruped is significantly different from those of a bipedal human. In a goat, the muscles of the legs are designed for a stiff-legged gait, and powerful muscles lever the neck and head against gravity.

Sturdivan exhibited a film to the members of the Assassinations Committee showing the effect of gunshot to the head of a goat. The legs kicked out and the back arched, movements consistent with the natural movements that a startled goat would be expected to make. . . .

The Panel’s mentioning of stiffening of the body suggests that they confounded the decerebrate rigidity exhibited by the goat in its death throes with the mechanism invoked by Sturdivan. . . .  The classic work of the English physiologist Denny-Brown on motor reflexes explained that decerebrate rigidity, also called the “stretch” reflex, is secured by a slow contraction process of the extensor muscles. It is a function of the spinal cord and is a postural reflex, which is to say that as the motor control centers in the brain stem receive feedback indicating a sagging of the body, it induces a reflexive stiffening of the trunk and limbs to break the fall. The arching of the back and agonistic outstretching of the limbs characterizes this response. President Kennedy did not react in this way. The rearward movement of the head began at impact, without the delay or latency that characterizes the extensor reflex of decerebrate rigidity. . . .

Sturdivan explained his theory of a neuromuscular reaction as a mechanical stimulation of the brain stem incuding a massive neurogenic surge resulting in contraction of the skeletal muscles. Actually, neurologists recognize a convulsive reaction to brain damage as post-traumatic motor seizures. . . .  Such post-traumatic motor seizures occur with high incidence in penetrating head injuries. But, the muscular convulsions associated with destruction of the brain do not result from a massive surge of impulses from the brain, as was the case with the Moro reflex, but rather from removal of the control function that inhibits spastic, convulsive muscular seizures. Consequently there is an inherent delay or latency period before the onset of convulsions. There was no delay in the rearward movement of the President’s head.

Because a spastic movement toward the shooter is evidenced in some execution films, one or another of these neuromuscular phenomena must be involved in those cases. It is therefore plausible that someone suffering a catastrophic destruction of the brain from a shot in the head would respond with an explosive motor spasm. Thus, a brain-traumatized person in a sitting position might lunge backward caused by a thrust of the legs against the floor as posited by the HSCA Forensic Pathology Panel. It is also clear, however, that this did not happen in the case of President Kennedy. Slow motion examination of the Zapruder film by the ITEK corporation demonstrated that the head snapped backward first, with the shoulders following, with the body then toppling over backward and to the left. Had an explosive motor spasm occurred, a sort of Grand Mal seizure, the shoulders and the head would have jerked backward at the same time. Nothing like that happened.

One might even ask: why didn’t it happen? Would not the destruction of the brain result in a convulsive muscular spasm as it did in the test-shot goat? The obvious answer lies in the fact that the President’s spinal cord had been traumatized 5 seconds before the head shot. Without a functional spinal cord, the spasmodic muscular convulsions seen in head-traumatized victims cannot be induced. Sturdivan acknowledged in testimony that if the President’s spinal cord had been severed by the earlier shot to the base of the neck, then the neuromuscular reaction that he had postulated could not have happened.

But Sturdivan offered as evidence for the presence of cord function the “fact” that Kennedy had grasped at his throat wound. Sturdivan’s grasp of the evidence indicates a greater familiarity with the Warren Commission’s distorted version of events than with neuromuscular physiology. (Hear No Evil: Politics, Science, and the Forensic Evidence in the Kennedy Assassination, New York: Skyhorse Publishing, 2010, pp. 332-335)

[Tim Nickerson]

So you are still trying to salvage your misreading of Sturdivan’s testimony? Sad. I never said that Sturdivan used "decerebrate rigidity" as a synonym for "neuromuscular reaction." Go back and read my reply. Sturdivan was not a medical scientist of any kind. He made several mistakes when he talked about the medical aspects of Kennedy's movements. Part of the problem seems to be that you have not done enough research on the medical and ballistics evidence to understand what you are reading in some cases.

I haven't misread Sturdivan's testimony at all. You have. In claiming that Sturdivan was saying that  the neuromuscular reaction began about 1000 milliseconds after bullet impact, you were obviously working under the false assumption that he was using "decerebrate rigidity" synonymously with "neuromuscular reaction".

Here is some reading for you. This is Dr. Donald Thomas’s destruction of Sturdivan’s defense of the neuromusuclar-reaction theory. Dr. Thomas, a research scientist whose work has been published in peer-reviewed forensic journals, shows that Sturdivan got the anatomy wrong, got the muscle functions wrong, and got the medical science wrong, and that the goat film is irrelevant because of the enormous differences in goat and human anatomy and because the goat's movements do not duplicate Kennedy's movements. Dr. Thomas also explains why it would have been impossible—not just improbable or unlikely, but impossible--for a neurospasm to have caused Kennedy’s backward movement.

Thomas' area of expertise is the study of insects. Sturdivan's expertise is wound ballistics. Sturdivan has also had his work published in peer-reviewed forensics journals. One such being "BALLISTICS FOR THE NEUROSURGEON" published in Neurosurgery, which is the official journal of the Congress of Neurological Surgeons. His work has also been published in The Journal of Trauma and Acute Care Surgery, Journal of Surgical Research, and  Computers in Biology and Medicine, to name a few others. Thomas should stick to what he knows and quit embarassing himself by foraying into areas beyond his ken.

[Michael T. Griffith]

I haven't misread Sturdivan's testimony at all. You have. In claiming that Sturdivan was saying that  the neuromuscular reaction began about 1000 milliseconds after bullet impact, you were obviously working under the false assumption that he was using "decerebrate rigidity" synonymously with "neuromuscular reaction".

You don't even know what you're talking about. "Deceberate rigidity" is the same thing as "deceberate reaction." They are two terms for the same action, and Sturdivan used both as synonyms for "neuromuscular reaction." You can Google them and learn this for yourself.

Thomas' area of expertise is the study of insects.

Yes, his main field of expertise is entomology, but his research on forensic/ballistics/acoustics issues has been published in peer-reviewed journals, including Science and Justice. He has also had over 100 articles published in scientific journals.

Sturdivan's expertise is wound ballistics. Sturdivan has also had his work published in peer-reviewed forensics journals. One such being "BALLISTICS FOR THE NEUROSURGEON" published in Neurosurgery, which is the official journal of the Congress of Neurological Surgeons. His work has also been published in The Journal of Trauma and Acute Care Surgery, Journal of Surgical Research, and  Computers in Biology and Medicine, to name a few others. Thomas should stick to what he knows and quit embarassing himself by foraying into areas beyond his ken.

Wow, really? So that's your answer: Dr. Thomas doesn't know what he's talking about regarding human anatomy and neuro reactions? Wow, uh-huh.  Never mind that neuroscientists Joe Riley and Robert Zacharko have likewise said that the neuromuscular-reaction theory is nonsense, right? And never mind that you guys can't cite a single neuroscientist who is willing to say that JFK's backward movement could have been caused by a neurospasm, right?

I'm guessing that you probably did not even understand half of what Dr. Thomas said, but you just know that you can't accept his observations and arguments because they don't agree with your neuromuscular-reaction fantasy.

[Tim Nickerson]

You don't even know what you're talking about. "Deceberate rigidity" is the same thing as "deceberate reaction." They are two terms for the same action, and Sturdivan used both as synonyms for "neuromuscular reaction."

VS

So you are still trying to salvage your misreading of Sturdivan’s testimony? Sad. I never said that Sturdivan used "decerebrate rigidity" as a synonym for "neuromuscular reaction." Go back and read my reply.

Perhaps you are having a rough day? 

Again, Sturdivan was using "decerebrate reaction" synonymously with "neuromuscular reaction", but you err in assuming that he was using "decerebrate rigidity" synonymously with "neuromuscular reaction". He used "terminus of the decerebrate reaction" synonymously with "decerebrate rigidity".  "Decerebrate rigidity" is NOT the same thing as "decerebrate reaction". It is the end point of a "decerebrate reaction".

[Tim Nickerson]

Never mind that neuroscientists Joe Riley and Robert Zacharko have likewise said that the neuromuscular-reaction theory is nonsense, right? And never mind that you guys can't cite a single neuroscientist who is willing to say that JFK's backward movement could have been caused by a neurospasm, right?

Neuroscientist? Didn't Zacharko teach psychology at Carleton? Maybe I should ask Jordan Peterson what he thinks.