The Straight Dope

Go Back   Straight Dope Message Board > Main > General Questions

Reply
 
Thread Tools Display Modes
  #1  
Old 03-07-2006, 03:01 PM
Tevildo Tevildo is offline
Guest
 
Join Date: Nov 2005
Minimum fatal drop (somewhat morbid)

I'm working on a piece of fanfic with a friend at the moment, in which a character is killed by falling from a balcony onto a solid concrete floor. The character is reasonably athletic, but not a trained acrobat, so will make the best landing possible - in other words, not on his head.

What's the minimum distance he can fall to make this realistic? 30'? 50'? 100'? A number of stories would be just as good - 4, 6, 10? We don't need medical data, we just want to stop people saying "Ha! A fall from an n'th floor balcony isn't going to kill him!"
Reply With Quote
Advertisements  
  #2  
Old 03-07-2006, 03:12 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Quote:
Originally Posted by Tevildo
What's the minimum distance he can fall to make this realistic? 30'? 50'? 100'? A number of stories would be just as good - 4, 6, 10? We don't need medical data, we just want to stop people saying "Ha! A fall from an n'th floor balcony isn't going to kill him!"
Ain't no such animal. People have been killed falling from as few as a few feet, and have survived falls of thousands of feet. There's simply too many variables involoved to say a fall of X feet is definitely survivable, while a fall of Y feet is invariably fatal. One could, for instance, jump from the second floor of a building and land on one's feet on the concrete sidewalk below, but suffer a compound fracture of the femur which severs the femoral artery causing him to bleed to death.
Reply With Quote
  #3  
Old 03-07-2006, 03:14 PM
Tevildo Tevildo is offline
Guest
 
Join Date: Nov 2005
Quote:
Originally Posted by Q.E.D.
One could, for instance, jump from the second floor of a building and land on one's feet on the concrete sidewalk below, but suffer a compound fracture of the femur which severs the femoral artery causing him to bleed to death.
Excellent idea, thanks. Now we just have to decide how gruesome to make the description.
Reply With Quote
  #4  
Old 03-07-2006, 03:17 PM
mks57 mks57 is offline
Guest
 
Join Date: Dec 2003
I knew someone who killed herself by jumping off a first floor balcony, roughly ten feet above ground level.
Reply With Quote
  #5  
Old 03-07-2006, 05:08 PM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
Don't sweat the physics; just be descriptive of the aftereffect. The character doesn't have to die instantly. He can have a few moments when he tries to get up and move but feels something inside his body pull sharply, sending him dizzyingly back to his knees. His mouth fills with blood, making him cough a red spray over the backs of his hands. His fingers shake, smearing the tiny puddles, staining the floor. His eyes try to follow the patterns but can't focus. His head turns toward the sounds of running footsteps, concerned bystanders closing in on him. He tries to tell them he's okay, tries to tell them anything, but collapses on his side instead. His shattered ribs grind and creak but he can no longer hear them.
Reply With Quote
  #6  
Old 03-07-2006, 05:25 PM
WhyNot WhyNot is online now
Member
 
Join Date: Jul 2004
Location: Sweet Home Chicago
Posts: 30,399
Quote:
Originally Posted by Bryan Ekers
Don't sweat the physics; just be descriptive of the aftereffect. The character doesn't have to die instantly. He can have a few moments when he tries to get up and move but feels something inside his body pull sharply, sending him dizzyingly back to his knees. His mouth fills with blood, making him cough a red spray over the backs of his hands. His fingers shake, smearing the tiny puddles, staining the floor. His eyes try to follow the patterns but can't focus. His head turns toward the sounds of running footsteps, concerned bystanders closing in on him. He tries to tell them he's okay, tries to tell them anything, but collapses on his side instead. His shattered ribs grind and creak but he can no longer hear them.
Dan Brown, is that you?

Reply With Quote
  #7  
Old 03-07-2006, 05:52 PM
LiveOnAPlane LiveOnAPlane is offline
Guest
 
Join Date: Sep 2005
Quote:
Originally Posted by WhyNot
Dan Brown, is that you?

No, the description is too believable--this could, just possibly, happen.
Reply With Quote
  #8  
Old 03-07-2006, 06:20 PM
rbroome rbroome is offline
Member
 
Join Date: Jun 2003
Location: Louisiana
Posts: 1,887
Quote:
Originally Posted by Tevildo
I'm working on a piece of fanfic with a friend at the moment, in which a character is killed by falling from a balcony onto a solid concrete floor. The character is reasonably athletic, but not a trained acrobat, so will make the best landing possible - in other words, not on his head.

What's the minimum distance he can fall to make this realistic? 30'? 50'? 100'? A number of stories would be just as good - 4, 6, 10? We don't need medical data, we just want to stop people saying "Ha! A fall from an n'th floor balcony isn't going to kill him!"
FWIW, I have heard that iron workers stop worrying about the height after 30 ft. After about that height, it doesn't matter how far one falls.....
Don't have a cite though.
Reply With Quote
  #9  
Old 03-07-2006, 06:24 PM
Shagnasty Shagnasty is offline
Charter Member
 
Join Date: May 2000
Posts: 22,361
I heard somewhere (maybe even here) that a 14 foot fall onto concrete is the height where 50% of the fallees die from it. Seems kind of low but that is why I remembered it.
Reply With Quote
  #10  
Old 03-07-2006, 07:10 PM
HMS Irruncible HMS Irruncible is offline
Guest
 
Join Date: Nov 2004
Quote:
Originally Posted by WhyNot
Dan Brown, is that you?

But just before he died, he hacked up a piece of thyme and spit it on the sidewalk, where it landed with a wet plop in exactly in the shape of a pyramid.
Reply With Quote
  #11  
Old 03-07-2006, 07:23 PM
LiveOnAPlane LiveOnAPlane is offline
Guest
 
Join Date: Sep 2005
Quote:
Originally Posted by Brain Wreck
But just before he died, he hacked up a piece of thyme and spit it on the sidewalk, where it landed with a wet plop in exactly in the shape of a pyramid.
Well, yes, but was it a 3-sided pyramid or a 4-sided pyramid?
Reply With Quote
  #12  
Old 03-07-2006, 07:27 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Quote:
Originally Posted by LiveOnAPlane
Well, yes, but was it a 3-sided pyramid or a 4-sided pyramid?
There's no such thing as a three-sided pyramid. A four-side "pyramid" is a tetrahedron. A "real" pyramid has five sides.

That was extremely nit-picky, wasn't it?
Reply With Quote
  #13  
Old 03-07-2006, 07:27 PM
HMS Irruncible HMS Irruncible is offline
Guest
 
Join Date: Nov 2004
Quote:
Originally Posted by LiveOnAPlane
Well, yes, but was it a 3-sided pyramid or a 4-sided pyramid?
... thought Dr. Goodguy as he stroked his rugged but handsome chin on the way to the secret Trilateral headquarters bunker in the center of the earth on a supersonic black helicopter, which had appeared out of the earth in an almost supernatural way.
Reply With Quote
  #14  
Old 03-07-2006, 07:48 PM
Whack-a-Mole Whack-a-Mole is offline
Guest
 
Join Date: Apr 2000
Quote:
Originally Posted by rbroome
FWIW, I have heard that iron workers stop worrying about the height after 30 ft. After about that height, it doesn't matter how far one falls.....
Don't have a cite though.
I have heard it this way too. Or rather fall from the fourth floor and up you are done for which is close enough for government work (~40 feet).

What others say is true...very slight falls have killed people and then some have survived falling thousands of feet.

For your story you just want to keep it within the realm of believability for most people so under 30' is probably doable (although onto flat concrete [no slope to it] I am thinking 30' is pushing it).

FYI this page says:

"It is estimated that the human body reaches 99% of its low-level terminal velocity after falling 573m 1880ft which takes 13-14 sec. This is 117-125mph at normal atmospheric pressure and in a random posture.

(At the 1100 ft Emley Moor TV mast near me they reckon that you would reach terminal velocity (great term) well before hitting the ground)"
Reply With Quote
  #15  
Old 03-07-2006, 08:30 PM
Harriet the Spry Harriet the Spry is offline
Guest
 
Join Date: Jun 2003
Quote:
Originally Posted by Shagnasty
I heard somewhere (maybe even here) that a 14 foot fall onto concrete is the height where 50% of the fallees die from it. Seems kind of low but that is why I remembered it.
My husband the engineer tells me something similar, but with 10 feet. The technical term for the "dose" at which 50% die is the LD50 (lethal dose, 50). I found that quite sobering.
Reply With Quote
  #16  
Old 03-07-2006, 08:43 PM
Whack-a-Mole Whack-a-Mole is offline
Guest
 
Join Date: Apr 2000
Quote:
Originally Posted by Harriet the Spry
My husband the engineer tells me something similar, but with 10 feet.
Only 10 feet? I know I have jumped 10 feet before and was fine (did it fairly frequently when I was a kid). If it is only your head breaking your fall then I can see it but otherwise I find it hard to believe 10 feet is lethal to 50% of people who fall that far.
Reply With Quote
  #17  
Old 03-07-2006, 08:47 PM
Shagnasty Shagnasty is offline
Charter Member
 
Join Date: May 2000
Posts: 22,361
Quote:
Originally Posted by Whack-a-Mole
Only 10 feet? I know I have jumped 10 feet before and was fine (did it fairly frequently when I was a kid). If it is only your head breaking your fall then I can see it but otherwise I find it hard to believe 10 feet is lethal to 50% of people who fall that far.
I am not really sure of the height but these are falls, not jumps. Think falling off a ladder and hitting concrete.
Reply With Quote
  #18  
Old 03-07-2006, 08:57 PM
Nic2004 Nic2004 is offline
Guest
 
Join Date: Feb 2004
I once had a friend that worked building radio towers and once told me ,following a fall and hospital stay, that those in his business called a fall like his a "dead man's fall". "Why?" I asked. He said it was under 15 feet. It is called this because that distance is too short to twist and correct your posture but high enough to kill. A bit higher and you may still twist yourself aroung to try and land on your feet. Too low and you land on your head.
YMMV
Reply With Quote
  #19  
Old 03-07-2006, 09:04 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
The 10-foot figure seems far too low to me. From here:
Quote:
Inclusion criteria are falls from a minimum height of 10 feet. RESULTS: Of 1,410 patients admitted after a fall, 64 patients including 45 boys and 19 girls with a mean age of 7.4 years (range, 1 to 18) are included in this study. Fifty (78%) children fell from 20 feet or less (two stories) and 14 (22%) from height greater than 20 feet.

...

The overall survival rate is 98% with only one death after a fall greater than 50 feet.
Now, this obviously does not include victims who were not taken to the hospital because they were declared dead at the scene, but given the overall survivability statistics in this study, I find it difficult to believe that only 50% of people survive a fall from ten feet. Thirty seems more reasonable.
Reply With Quote
  #20  
Old 03-08-2006, 11:25 AM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by Q.E.D.
From here
That study has a bias though, in that the subjects are children. The composition of human flesh, muscle tissue and bone is not hugely different when comparing a 10-year old and a 30-year old, but if the child weighs 40 kilograms and the adult weighs 80 kilograms, the adult is going to hit the concrete with much greater force, inviting more broken bones and bleeding and whatnot for overall greater (and possibly fatal) injury.
Reply With Quote
  #21  
Old 03-08-2006, 12:09 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Quote:
Originally Posted by Bryan Ekers
That study has a bias though, in that the subjects are children.
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 Ek = 1/2mv2, 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.
Reply With Quote
  #22  
Old 03-08-2006, 12:24 PM
Ludovic Ludovic is offline
Charter Member
 
Join Date: Jul 2000
Location: America's Wing
Posts: 23,261
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.
Reply With Quote
  #23  
Old 03-08-2006, 12:31 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Good points, Ludovic.
Reply With Quote
  #24  
Old 03-08-2006, 01:17 PM
Fish Fish is offline
Guest
 
Join Date: Nov 2000
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).
Reply With Quote
  #25  
Old 03-08-2006, 02:47 PM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by Q.E.D.
Correction: the average subject is a child.
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.

Quote:
Also, remember the equation for kinetic energy is Ek = 1/2mv2, so that velocity is the more important parameter, which will be the same for all subjects from a given fall height.
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.
Reply With Quote
  #26  
Old 03-08-2006, 04:22 PM
FordPrefect FordPrefect is offline
Guest
 
Join Date: Oct 2001
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.
Reply With Quote
  #27  
Old 03-08-2006, 05:26 PM
Whack-a-Mole Whack-a-Mole is offline
Guest
 
Join Date: Apr 2000
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).
Reply With Quote
  #28  
Old 03-08-2006, 05:55 PM
Harriet the Spry Harriet the Spry is offline
Guest
 
Join Date: Jun 2003
I take back that statement about 10 feet. From this site, median lethal height is given at 48 feet

http://list.uvm.edu/cgi-bin/wa?A2=in...y&F=&S=&P=5170
Reply With Quote
  #29  
Old 03-08-2006, 11:11 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Quote:
Originally Posted by Bryan Ekers
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.
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.
Reply With Quote
  #30  
Old 03-09-2006, 05:19 AM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by Q.E.D.
Well, yes. You're taking this a lot more seriously than I am.
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.
Reply With Quote
  #31  
Old 03-09-2006, 05:54 AM
SentientMeat SentientMeat is offline
Guest
 
Join Date: Nov 2002
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, v2=u2 + 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.
Reply With Quote
  #32  
Old 03-09-2006, 09:07 AM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by SentientMeat
a grass bus
1967 Volkswagon van?



Like, groovy, man.
Reply With Quote
  #33  
Old 03-09-2006, 09:12 AM
Kalhoun Kalhoun is offline
Guest
 
Join Date: Dec 2002
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.
Reply With Quote
  #34  
Old 03-09-2006, 09:21 AM
SentientMeat SentientMeat is offline
Guest
 
Join Date: Nov 2002
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.
Reply With Quote
  #35  
Old 03-09-2006, 11:00 AM
Bryan Ekers Bryan Ekers is online now
Guest
 
Join Date: Nov 2000
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.
Reply With Quote
  #36  
Old 03-09-2006, 12:38 PM
chrisk chrisk is offline
Charter Member
 
Join Date: Nov 2003
Location: Southern ontario
Posts: 5,981
Quote:
Originally Posted by Q.E.D.
There's no such thing as a three-sided pyramid. A four-side "pyramid" is a tetrahedron. A "real" pyramid has five sides.

That was extremely nit-picky, wasn't it?
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.
Reply With Quote
  #37  
Old 03-09-2006, 12:45 PM
Q.E.D. Q.E.D. is offline
Charter Member
 
Join Date: Jan 2003
Location: Richmond, VA
Posts: 22,536
Quote:
Originally Posted by chrisk
Yes... and I don't think it's inarguably correct to refer to the bottom face as a 'side'.
Maybe you missed the little winky smiley that says (at least to MY mind) "This post not to be taken entirely seriously".
Reply With Quote
  #38  
Old 03-09-2006, 01:00 PM
gabriela gabriela is offline
Guest
 
Join Date: Mar 2006
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.
Reply With Quote
  #39  
Old 03-09-2006, 01:03 PM
Fish Fish is offline
Guest
 
Join Date: Nov 2000
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.

Quote:
Originally Posted by SentientMeat
Imagine a large cube of ground driving around like a bus.
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?
Reply With Quote
  #40  
Old 03-09-2006, 01:11 PM
gabriela gabriela is offline
Guest
 
Join Date: Mar 2006
Quote:
Originally Posted by SentientMeat
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, v2=u2 + 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.
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.

We need a better example than a bus.
Reply With Quote
  #41  
Old 03-09-2006, 04:02 PM
lno lno is offline
Member
 
Join Date: Oct 2000
Location: In the state of denial
Posts: 4,827
Don't stop talking now, gabriela. That's honestly fascinating.
Reply With Quote
  #42  
Old 03-10-2006, 04:13 AM
SentientMeat SentientMeat is offline
Guest
 
Join Date: Nov 2002
Quote:
Originally Posted by gabriela
Hate to nitpick, SentientMeat, as sentient meat is one of my favorites
Why thank you, and pick away - that's what General Pedantry Questions is for.

Of course I bow to your expertise in statistical analysis of what actually kills people from falls and bus impacts, since I myself only have a single anecdote of a girl I knew dying (nearly) instantly from head trauma after being hit by a bus in a 20 mph zone. In fact, I'd be surprised if too many people are hit by buses travelling much more than about 20 mph, since busy traffic, driver wariness in areas with lots of pedestrians, and the usual application of at least some braking before impact would tend to limit impact speed - I'd still suggest that 35+ mph full side impacts alone would be largely fatal, and I guess the fact is that falling people do generally get an arm or leg between their head and the ground. So, yes, I suppose the bus model isn't quite accurate and it might well be more like 30 ft for 50% lethality falls, and I think Tev's unlucky chap is going to have to flip over the lower balcony and land on his head or some ground-based protrusion to die plausibly.

And Fish is also clearly in a better position than me to analyse mortality statistics from slips or faints or whatever. Again, my only anecdotes are our alcoholic ex-drummer who fell over onto the pavement, and an old lady in Liverpool who slipped on some ice, both again dying from head trauma. I assumed these stories weren't that uncommon, but I'll retract "regularly" unreservedly.
Reply With Quote
  #43  
Old 03-10-2006, 04:29 AM
mittu mittu is offline
Guest
 
Join Date: Mar 2005
Not completely on topic but something I found interesting all the same is a statistic I heard on the British T.V. programme Q.I. (Quite Interesting). The presenter said that the chances of survival for a cat falling from height decrease up to the 7th floor but the survival rate increases for falls higher than 7 floors. This being due to a combination of the cat having time to right itself to prepare for landing on it's feet and also being able to "glide" to some degree by going spread eagle to reduce impact speed. Like I said it isn't entirely relevant, but it is QI
Reply With Quote
  #44  
Old 03-15-2006, 12:28 PM
Maus Magill Maus Magill is offline
Not a real doctor.
Charter Member
 
Join Date: Dec 2003
Location: Nolensville, TN
Posts: 6,195
Quote:
Originally Posted by Brain Wreck
... thought Dr. Goodguy as he stroked his rugged but handsome chin on the way to the secret Trilateral headquarters bunker in the center of the earth on a supersonic black helicopter, which had appeared out of the earth in an almost supernatural way.
I have continued this over here.
Reply With Quote
  #45  
Old 03-15-2006, 01:16 PM
Fish Fish is offline
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by mittu
Not completely on topic but something I found interesting all the same is a statistic I heard on the British T.V. programme Q.I. (Quite Interesting). The presenter said that the chances of survival for a cat falling from height decrease up to the 7th floor but the survival rate increases for falls higher than 7 floors.
I believe Cecil covered this at some point. Such a study was done, but it was inconclusive, since there was no way to count the cats who jumped or fell at 7 stories plus and turned into cat pancake. The vets who saw cats only saw the ones brought in who had a chance to be treated and not the flatcats who were peeled up like a fruit roll-up and frisbeed into the trash.

I'll try to find that link.
Reply With Quote
  #46  
Old 03-15-2006, 03:53 PM
gabriela gabriela is offline
Guest
 
Join Date: Mar 2006
Hey, we made Threadspotting!

I stopped posting to this thread because it seemed to be going away quietly, and I assumed the OP had everything needed to off a character without being ridiculed.

But I think you all are right: we have to say what killed him. The OP specified no head trauma. Details like the bloody drops spattering from the mouth are cool too.

I think we can do one of two things: either come up with a common injury that you can sustain falling off a balcony without falling on your head, or come up with a weird congenital problem nobody would ever know they had, so they die on impact.

Common injury without head injury... um... has to fall on heels or knees on floor, hunh? Could the character bounce and skid, the way some of my pedestrians struck by cars have bounced and skidded? You know, red scrape across skin at first impact site, slightly less red at second bounce site, nearly yellow at third bounce site, purely yellow and dry at fourth skid site. (Abrasions are only red while you're alive; postmortem abrasions are yellow, because subcutaneous fat is yellow, and if you have a blood pressure of zero, your scrapes don't bleed. I am always excited when I can track the course of a decedent from live to dead by the changing colors.)

But that didn't kill him. Bones! I know he's dead, but from WHAT! Um... okay... can he land on his chin, and break his neck? It'll be the tiniest little abrasion, but he'll be dead on third bounce.

Or he could land chest first on something upholstered and soft, and die from commotio cordis. That'll work. He'll look puzzled, get out two words, and go limp. Even immediate defibrillation won't save him. (Classically softball to chest in young athletes. The heart has to be in exactly the right phase of the cycle - physicians who care for live people, help me out here.)

Oh! I know!! Have him land on his butt, and his pelvis fractures away from his spine in two places, and he gets retroperitoneal bleeding from a thousand tiny veins too small to repair surgically! Then it takes him a couple of hours to die - plenty of time for moving deathbed scenes - but, even with the utmost in medical care, he's a goner. Even the interventional radiologists won't be able to embolize enough of them.

As for congenital anomalies or unsuspected natural disease - He could have a mild Arnold-Chiari that he never knew he had, and the impact jolts his brain loose just enough to cause him to die seizing, in status epilepticus. Or an atrial myxoma, part of which fractures off from the impact, and goes out the aorta, and embolizes one of his coronary arteries.

I admit that one's a stretch,
Gabriela
Reply With Quote
  #47  
Old 03-15-2006, 10:26 PM
Capa84 Capa84 is offline
Guest
 
Join Date: Jul 2005
Quote:
Originally Posted by Bryan Ekers
That study has a bias though, in that the subjects are children. The composition of human flesh, muscle tissue and bone is not hugely different when comparing a 10-year old and a 30-year old, but if the child weighs 40 kilograms and the adult weighs 80 kilograms, the adult is going to hit the concrete with much greater force, inviting more broken bones and bleeding and whatnot for overall greater (and possibly fatal) injury.

Unless I missed it, this study did not specify what surface the fls occurred on. A fall out of a bedroom window onto a flower bed from 20 feet seems much more desirable than a fall from 10 feet onto concrete.
Reply With Quote
  #48  
Old 03-16-2006, 04:30 AM
Fish Fish is offline
Guest
 
Join Date: Nov 2000
Quote:
Originally Posted by gabriela
But I think you all are right: we have to say what killed him. The OP specified no head trauma. Details like the bloody drops spattering from the mouth are cool too.
Actually, he didn't specify no head trauma, he just specified that the character wouldn't land on his head. I assume that means the character would attempt to make a good landing, either on his feet, knees, hands, or some combination thereof; but he could subsequently hit the ground with his head, I suppose.

Heck, no head trauma? What fun is that? We'd rule out all those nice intercranial hemorrhages and stuff.

If the character did attempt to brake his fall by using his hands or feet, he might have incidental injuries such as bilateral fractures of the ulna and/or radius. (I see this happen with some frequency with ATV accidents: some joker goes over a dropoff with his four-wheeler and braces for impact with his arms stiffened, breaking them both in the process of landing.)

I've even seen people try to stop themselves from falling on the way down really, Hollywood needs to do a better job at showing us how not to get hurt when we're jumping off buildings. One carpenter, claw hammer in hand, managed to stab the claw of the hammer into a plywood wall to slow his fall. For his effort he was rewarded with dislocations of his shoulder, elbow, and multiple dislocations in his hand and fingers. Lovely.
Reply With Quote
  #49  
Old 03-16-2006, 04:33 AM
Fish Fish is offline
Guest
 
Join Date: Nov 2000
Arrrgh, intracranial hemorrhages. An intercranial hemorrhage would be pretty difficult if you weren't a hydra.
Reply With Quote
  #50  
Old 03-16-2006, 07:33 AM
The Seventh Deadly Finn The Seventh Deadly Finn is offline
Guest
 
Join Date: Mar 2003
Quote:
Originally Posted by Bryan Ekers
Snopes has a photo of a guy who fell partly onto a steel fence and had his head taken clean off.
I've seen the photos. It wasn't that clean. Ecch.
Reply With Quote
Reply



Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 08:35 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.

Send questions for Cecil Adams to: cecil@chicagoreader.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Publishers - interested in subscribing to the Straight Dope?
Write to: sdsubscriptions@chicagoreader.com.

Copyright 2013 Sun-Times Media, LLC.