How does getting hit (like a punch to the jaw/face) knock one out? I’m sure it has an obvious answer, but I’d just like some confirmation.
It is fairly straightforward, although not completely.
The brain is suspended inside the skull in a bath of cerebro-spinal fluid. This cushions it from shocks and protects it.
A concussion (which is the technical term for being dazed or knocked out by a blow to the head) occurs when the head is subjected to sudden acceleration. The skull accelerates faster than can be compensated for by the fluid bath, and the brain smacks against the inside of the skull. This causes some of the neurons of the brain to fire, some to be bruised, and some to be destroyed. The neurons take a little while to recover after firing (for any reason), and the period of unconsciousness or diminished consciousness that follows is what we call ‘being knocked out’.
The reason that blows to the jaw are more likely to create concussions and knockouts is that the head rotates around the axis of the spinal column. Being hit ‘on the button’, or the side of the chin, produces the greatest rotation of the head because the chin is the point furthest from the axis of rotation, and therefore subject to the greatest leverage. Same reason that your arm is easier for someone else to move when it is straight out to your side than when it is bent close to your side. The same force will produce a greater effect if the leverage is longer.
Concussions are classed by severity. Level 1 is being dazed, but without losing consciousness completely. Level 2 is complete loss of consciousness for a minute or less. Level 3 is more than a minute but less than an hour. Level 4 is over that.
All concussions are serious. All concussions involve brain damage, which can never heal. Muhammed Ali, for instance, was knocked down only four times in his pro career, and knocked out once each as an amateur and a professional, and he is suffering from Parkinsonism as a result of the thousands of level 1 concussions he experienced.
Regards,
Shodan
Shodan, I found this article on Pub Med that calls your hypothesis into question.
Neurol Clin 1992 Nov;10(4):907-19
Trauma and movement disorders.
Goetz CG, Pappert EJ
Emphasis mine. Can you find any refs for the concussion leads to Parkinson’s notion?
CB
Take a peek at:
http://boards.straightdope.com/sdmb/showthread.php?threadid=14630
for previous answers, including an explanation of the “glass jaw” and a device to prevent it!
FWIW the head (brain) can tolerate much more front-to-back (or back-to-front) acceleration than it can side-to-side motion.
For a boxer, giving you a round-house(?) to the side of the head is much more likely to knock you out than a punch dead-on into your face. Obviously a concussion can happen with both but it’s just easier to get one from side-to-side motion.
Here I thought I’d have to cite my reference in the earlier thread, and matt’s a step ahead of me. Good heads-up, bro.
Hi, choosybeggar -
I don’t think Ali has Parkinson’s disease, but Parkinsonianism. That is, he has many of the symptoms associated with Parkinson’s disease (shuffling gait, blurred speech, a frozen expression, among others) but these symptoms are not caused by whatever it is that causes Parkinson’s disease, but by chronic brain damage. They are different syndromes that appear similar.
I obviously have never examined Ali and don’t have access to his medical records, but I remember reading about him several years ago when some crackpot in the Philippines convinced Ali that his neurological symptoms were not caused by boxing but by poisoning by pesticides. The article I read quoted a doctor who I believe did examine Ali who mentioned that Ali has enlarged ventricles in his brain, which are the spaces between the hemispheres of the brain. The brain damage Ali has suffered (he has been fighting the best amateur and professional boxers of three generations, ever since he was twelve years old till he was almost forty) has reduced the size of his brain and made him a damaged person.
There is another syndrome that boxers can suffer from called ‘pugilistica dementia’, which involves a dementia similar to that found in Alzheimer’s disease. Don’t think Ali has this, at least not yet, but as he ages and continues to lose brain cells (as we all do as we age) his symptoms are likely to increase.
Both Rocky Graziano and Sugar Ray Robinson suffered from Alzheimer’s or something similar, so they may have suffered some form of brain damage during their careers as well, and Jerry Quarry, well known heavyweight contender of the '60s, was also basically disabled as a result of his brain damage. Wilfred Benitez, who won a world professional title at the age of 17 (and got knocked out by Sugar Ray Leonard for the world welterweight title) is under the care of his mother after being knocked senseless several times, although if Cus D’Amato’s girlfriend is to be believed (Benitez lived with them for a while when Benitez was preparing for a fight) Benitez was not too sharp long before he ended his career.
I will see if I can dig up anything on Medline to show the association between traumatic brain injury and Parkinsonianism if I get a chance. I will be out of town for a week, so it won’t be for a few days, but let me see what I can find.
Regards,
Shodan