I am a mechanical engineer studying mechanisms of brain trauma. Of the mechanisms that I have studied, I found the evidence of brain trauma as a result of thoracic pressure surge only due to blast waves. I would like to know if any other kind of impact in the thorax could lead to brain trauma due to thoracic pressure surge. For eg. if someone gets kicked in the thorax portion are there any chances of their experiencing brain trauma.
This is an interesting theory. I am definitely not a trauma specialist and have only rudimentary knowledge on biomechanics, but I could imagine that the (incompressible fluid) pressure wave may (in theory!) be transmitted through the vascular system, specifically the large thoracal and cervical veins (similar to the so-called Valsalva maneuver). On the other hand I would be surprised if this pressure wave would be sufficient to cause significant CNS trauma (if the head itself is not accelerated e.g. during a blast).
...one further suggestion: A penetrating gunshot into the thorax (with high-energy projectiles) should lead to an enormous temporal pressure surge, e.g. by cavitation. Following your theory this may (indirectly) carry the risk of brain trauma.
The thorax of human beings or for that matter of any animal is composed of organs having high air and fluid content. For e.g. the lungs in the thoracic cavity are basically membranous bags full of air. If the explosion shock wave hits the thorax, a compression wave is transmitted to the lungs causing compression of the lungs, hence a subsequent surge of blood to the brain. Increase in the intracranial pressure could lead to the collision of brain against the skull, resulting in abrasion of the brain tissue, or even rupturing of the vascular tissue. Concerning the example of gunshot, it comes under the heading of ballistics and for ballistics the thoracic pressure surge is a proven mechanism. My question is that can the same be said for sports injuries or accidents causing a thoracic pressure surge.
So far as cavitation is concerned. I do not think thoracic pressure surge could lead to creation for negative pressure in any area of the brain be it temples or any other. Because there is an increase in blood flow towards the brain whereas cavitation is induced because of negative pressures. However, if you mean that once the pressure recedes, then cavitation could be possible.
If you know of any article dealing with thoracic pressure surge due to non-ballistic injuries please share. Thanks for discussing @Just Genius
The odds of brain trauma from a blow to the thorax depend upon the biomechanics of the injury. There are a few factors to consider: capacitance of the venous system, the arterial system's ability to mitigate pressure waves (and thus maintain a relatively constant blood pressure), and the magnitude of the injury.
For a blast wave, the possibility of a clinically meaningful vascular pressure wave is most likely no because there is almost no momentum in a shock wave. Brain effects are likely due to primary blast wave effects upon the brain.
For blunt trauma, maybe, but I think it is doubtful. A piston effect on the thoracic wall theoretically could cause such a surge, but probably at the expense of major damage to the thorax, lungs, heart, and great vessels. Who cares about brain injury if the vena cava is ruptured?
The blunt trauma effect of an air mass behind a shock wave has been proposed as an injury mechanism. Outside of water, however, it seems an unlikely possibility until the explosion is extraordinarily large, say a small nuclear weapon or its conventional equivalent. Victims will have other concerns from exposure to an explosion of that size.
@Bruce Capehart :The piston effect that you talk about is what I am basically looking for. Irrespective of whether the major organs have sustained heavy damage, do you think that it could result in rupturing of the blood vessels in the brain?
@ Wei Zhao: Can you please give me a reference for this? I think this is what I have been looking for.
This concept is what I learned in my advisor's class. I was not able to found a reference for it. However, I found another paper which could be helpful.
Based on this Thoracic mechanism as discussed in the following paper, one experiencing a blast wave around chest like the blast from airbag could sustain brain pressure-induced injury.
Article A Thoracic Mechanism of Mild Traumatic Brain Injury Due to B...
@Wei Zhao: Thanks a lot. I already read this paper but it does not mention anything about non-ballistic injuries. Can you please tell me the name of your advisor? Thanks
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