Correction: the average subject is a child. At least some of the study participants are between 13 and 18 (children in the legal sense only, generally not biologically), when most people have reached a significant percentage of their final size. Unfortunately, the abstract doesn’t break the figures down by age, and I’m not willing to pay to read the entire study. Also, remember the equation for kinetic energy is E[sub]k[/sub] = 1/2mv[sup]2[/sup], so that velocity is the more important parameter, which will be the same for all subjects from a given fall height. The G forces involved in the impact will also be similar, and it is these forces which primarily cause injury.
Even allowing for differences in body mass, I still think the study demonstrates that the 10-foot 50% fatality figure is too low. Most falls are from 10 feet or less, so naturally there will be a larger number of fatalities at this level, but this is not a useful statistic here.
In addition, you have some reporting bias in that the vast majority of times when a person fell from 10 feet and survived are NOT reported. It’s easier, although still hard, to believe that half the people who, say, went to the hospital or called emergency services for a 10 foot fall died since they would tend to have worse injuries, such as a cracked skull.
In fact, it wouldn’t surprise me if it makes 10 foot falls seem even worse than they are with regards to 20 foot falls, even given the same impact force. After all, you are more psychologically likely to just shrug off a 10 foot fall, whereas a 20 foot fall, even if you are okay, you are likely to go to the doctor anyway to have it checked out.
My stepfather was a contractor for many years. He did reroofing and built houses and suffered multiple 10 foot falls from walking along the (open) joists of the second story. Sometimes those falls were onto the bare plywood of the first floor, and occasionally onto the concrete pad that had been poured for the garage.
Either he was fantastically and freakishly lucky and walked away from most of those with only minor muscle strains and bruises, or that “50% of falls from ten feet are fatal” thing needs to be better quantified.
Furthermore, I read X-ray reports that come from the ER of the local county hospital. Most falls classified as from a height of 10’ aren’t that serious, though one could easily imagine a scenario where such a fall might do serious injury. Just as a f’rinstance that doesn’t require a single broken bone: rupture your bladder on impact and die from peritonitis (paging Virginia Rappe).
The title suggests otherwise, but even if you’re willing to arbitrarily decide older teens are indistinguishable from adults, the average age of the 64 subjects analyzed is only 7.4 years.
If it’s the same, then how is it relevant? My point is about the arithmetic increase in G forces associated with larger mass. Consider a ten-foot fall in which an adult subject and a child subject land with most of their weight on, say, their right knees. Unless the adult patella is twice as strong as the adolescent patella (seriously, is it?), would it be fair to say that the adult (with twice the overall mass) runs the greater risk of a broken kneecap, with attendant bleeding and other injury?
In any case, no study is going to matter to an individual case. If the OP makes his character fall from a height of 20 feet or so onto a hard surface, only the most nitpicky of readers will claim (falsely) that a fatality is impossible, and the OP can rightly tell them to get a life.
I have fallen 10 feet and landed straddling a scaffold, I had a bruise about 4 feet thick on my right inner thigh, but I still had my right testicle 2 inches away from the bruise. :eek:
It should be noted that the landing is very important in most falls. Land exclusively on your head on concrete and a fall from 10’ will likely end you or at the least be very serious. Land on an outstreched hand and you will probably break your wrist or arm at the least. Spreading out the force of the landing is the key to best chances to walking away with the least injury. IIRC the ideal is to land on your side (forgot where I read that). Yes, in martial arts classes landing on your back is ideal with arms out a bit but those are generally on mats. Again IIRC the problem with long falls landing on your back is your head will snap back and bash the ground as well. On your side there is less chance of the head impacting the ground (you might break your shoulder or arm but better that than your head). I should note I read somewhere on boxing that the brain can withstand sloshing front-to-back better than side-to-side so maybe this would be a consideration for landing on your side. Perhaps the resident docs can weigh in on the matter (IANADoctor).
Of course, not everyone is able to (or thinks to) spin themselves into an ideal position for a fall. I know I can (and have) but I know others who would never adjust their position ideally (my mom for one…she falls she will definitely put out her hands or just let gravity drop her as it will).
Well, yes. You’re taking this a lot more seriously than I am. I was just showing that ten feet is probably too small a number for a 50% fatality rate, not looking for an exact scientifically-determined figure. The study I liked to was sufficient for that purpose, IMO. And, as you can see from the post above, I was right.
Well, in addition to writing purple prose (example above; I also have a cool death scene in one of my Star Trek fanfics), I have a degree in Management Information Systems (i.e. business statistics) which I feel compelled to use every now and then because my job certainly doesn’t call for it.
Sigh.
Imagine a large cube of ground driving around like a bus. A 10 ft fall is equivalent to being hit by that piece of ground at (hang on, v[sup]2[/sup]=u[sup]2[/sup] + 2as, u=0, a=10m/s/s, s= 3m, so v = sqrt(60) = 8 m/s, and 10m/s = 22 pmh) about 18 mph. Now, many people might well survive the equivalent of being hit by a bus at 18 mph, but many won’t. And as the bus increases its speed, it will kill more and more of those it hits (from the side, you’ll note - supposedly the safest way to land). A 30ft fall puts the bus at around 36 mph, which is almost invariably fatal.
So from fall alone onto a hard surface, I could well believe >50% lethality from a height of less than 20ft. (48 ft = 40 mph!). The variability would come from the surface one fell onto: a wooden bus would be less lethal, and a grass bus less lethal still.
I was watching The Tomorrow Show with Tom Snyder a thousand years ago. A guy jumped out of a plane and his chute didn’t open. He landed on his feet, went into the ground like up to his mid-shins or knees or something, and his thighs jammed up through their sockets. He lived.
You need something odd to happen if you want people to buy into a short-fall death. Something like landing on a marble and slipping, bashing the head, etc. Or maybe a short jump but a bird flew into the path and the guy gets pecked in the eye and dies of a brain infection or something. I used to regularly jump out of my friend’s 2nd story window. It’s not scary unless you throw something unexpected into the mix.
As others have said, there is a big difference between jumping (in which one can indeed use one’s legs as shock absorbers quite effectively, spreading the deceleration over a longer period/distance and thereby substantially decreasing the force on any vital organs) and a fall. Heck, old people, drunk people or anyone else who has trouble deploying a limb as such an absorber regularly die from falling over.
I suppose the character could fall across a steel railing or something; a good hard narrow smash in the ribs, leading to a collapsed lung, internal bleeding and death.
Snopes has a photo of a guy who fell partly onto a steel fence and had his head taken clean off. Of course, if you put that in a novel, the reader would find it improbable.
Yes… and I don’t think it’s inarguably correct to refer to the bottom face as a ‘side’. Sometimes it makes sense to refer to all the surfaces of a solid as sides… sometimes it only really makes sense for the surfaces that are towards the side in a given orientation - not the top or the bottom.
When I was in a general surgery residency in 1994, in Brooklyn, NY, where a great many people went out of windows of tall buildings (voluntarily or not), one of the attending physicians did a study on how many stories were required for a lethal fall. I do not know if he ever published it beyond presenting it to the surgical staff; his last name was Scalea.
I do recall his data.
The LD-50 was four floors.
The LD-95 was six floors.
On hearing this, one of the best of the nurses in the trauma ER said: “I’d like to be mayor of NYC for one day. I’d pass one law. All buildings must be twelve stories or higher, and no windows till the twelfth floor.”
I took care of somebody who was trying to make it to be one of the 5%. He had gone out of a sixth story window - don’t remember why or how. I was one of the many residents who passed through his life during the seven months he spent in the ICU. He had shattered his heels, his femurs, his hips (quite correct about putting the head of the femur out of the socket - posterior dislocations), several of his vertebrae, and his ribs. He had given himself shock lung, chronic heart, liver, and kidney failure, and innumerable infections. I remember the incredible lassitude with which he would lift an arm for the blood pressure cuff. He had memorized the routine of the ICU; he was busy concentrating on not dying.
He was twenty-three.
With up to date surgical treatment, survivals might be slightly better. However, I think you can take 4 floors = half the people die as a reasonable starting point.
Now that I am a medical examiner, I frequently examine people who have died from falls. Usual cause of death is head injury. Sometimes a staircase can be more hazardous than a three-story fall.
If it isn’t already obvious, I have to concur that the best way to describe a fatal fall from any height is to be specific. Did a rib puncture a lung? Did the patient die from internal bleeding? Did he die from a closed head injury? Did he die instantly, or of some secondary infection a few days later? A fatality could happen, in theory, at any hight; but so could survival.
That’s an interesting idea, but the comparison to bus vs. pedestrian MVA fatality rates isn’t appropriate. Being hit by a bus often includes two blunt traumas: being struck by the bus, then bouncing onto the ground at roughly the same speed, with your head likely moving faster than your body and striking the ground with some force.
Also, please do recall that I read X-ray reports all day along that arrive from the biggest emergency room in the county; inevitably included are a dozen GLFs (ground level falls) of elderly patients per week (or more). The most common injuries are comparatively minor (intertrochanteric fracture of femur, fracture of pelvis, fracture of distal ulna/radius) compared to instant death.
I won’t dispute that fatalities can occur from falling over, but if the elderly “regularly die from falling over” then my newspaper has been really skimping on the obituaries page lately. Can you quantify what you mean by the phrase or explain why it doesn’t tally with my experience reading these reports?
Hate to nitpick, SentientMeat, as sentient meat is one of my favorites, but if you are estimating death rates of pedestrians from mph, there is more information needed. You see, the sudden deceleration from hitting the ground is not exactly like the way people die when hit by a bus.
When hit by a car, the vast majority of people are not run over; they are run under. The lower legs break, sending them into the air. They usually strike the hood of the car, often with the back of the head impacting the windshield, “starring” the windshield, possibly leaving a few hairs in the glass. They then go over the top of the car. They are still alive, although with broken legs, and maybe with head pain from the nonfatal windshield impact. They die when they hit the ground. They die from head injury.
A person hit by a bus would actually be run over. There would be two separate sets of injury. The first would be when the kinetic energy of the bus struck the pedestrian. Mass times velocity squared. This is the closest approximation to the ground that your example offers. The likelihood is that they would incur lots of fractures, but not be killed by simple impact. If they were killed, the injury I have seen most often, in my autopsies as a medical examiner, is rib fractures, with the free ends of the ribs bending inward at the moment of impact, to perforate heart and lungs. This is a vanishingly rare injury in fatal falls.
If they are then run over, they incur compression injuries beneath the tire marks, which makes them, in layman’s terms, squuushed. They are not squshed the same way that people who land after high falls are squished: very different sets of internal injuries. This is not what you wanted from your example.
When people are hit by the side mirror of a car, and spun off sideways, which is a better model of bus impact, they generally do not die even when the vehicle is going very fast. I see broken arms very often. Those who die, do so because they fall on their heads with enough mass times velocity squared to squush it.
