BS: The physics of a fall

Subject: BS: The physics of a fall
From: Mrrzy
Date: 19 Apr 07 - 02:04 PM

Help, you math and physics people.

Say I weigh 85 kilos, and usually walk at about 5 km/hour. But I was running down the stairs when I tripped, so I'm assuming I was going faster than that. And speeding up as I hit.
Upon tripping, I landed - with all my mass times acceleration- on about 3 square centimeters of shin, on the edge of a concrete step - no give at all. So:

How much energy was actually transferred to my leg in the fall?

Now, I basically have a tremendous bruise - my entire lower leg is swollen and the bruising extends to my ankle and half-way up my thigh. The swelling looked for all the world like somebody had shoved an American football into my leg, with the stitching being the little scrape on my shin. All the rest of the injury is inside my leg - I had to have crutches for the first time in my life, I missed several days of work and now that I'm back, it's swelling and painful again (RICE therapy doesn't work at the office). So:

Is it possible that the hydrostatic (lipostatic?) force from all that energy being transferred suddenly to my leg caused something more like a blast injury than a boo boo (the bruise on my shin)?


Thank you all for your kind and thoughtful analysis.

Subject: RE: BS: The physics of a fall
From: Ebbie
Date: 19 Apr 07 - 03:24 PM

I don't know the scientific formulae- but commiserations anyway.

Subject: RE: BS: The physics of a fall
From: Greg B
Date: 19 Apr 07 - 03:31 PM

"How much energy was actually transferred to my leg in the fall?"

Enough.

Subject: RE: BS: The physics of a fall
From: Sorcha
Date: 19 Apr 07 - 03:38 PM

I'm surprised you didn't break at least the shin bone, let alone something else! Hope you mend fast!

Subject: RE: BS: The physics of a fall
From: Jean(eanjay)
Date: 19 Apr 07 - 03:39 PM

work done/energy = force x distance

Somebody else's turn now!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 19 Apr 07 - 03:40 PM

Had it been a free fall, it would have accelerated at 32 ft/sec per second of time falling. You were pretty close to the ground at the low end, but suppose you were moving at 7000 meters per hour, 116.6 m per minute, about 2m per sec. If your fall took .5 seconds, which seems reasonable, the increase would be about 4.9 m/sec, so assume your final velocity on impact was 6.9 m/sec.   

If I recall basic physics correctly, which is always problematical, kinetic energy = 1/2 mass * v^2. This would equate to 42.5 * 47.61 or about 2023 joules of energy. About 675 joules per square cm.

I hope John H will come check my work, though. Insult to nerves can sometimes cause reaction in a region rather than a single point of impact in my experience. I would be more inclined to attribute it to nerve insult and shock than to transmitted hydrostatic pressure.


A


A

Subject: RE: BS: The physics of a fall
From: Slag
Date: 19 Apr 07 - 03:47 PM

Correction: 32 ft per second SQUARED as this is acceleration. Add to the speed of forward momentum. Roughly 15 to 20 miles an hour max. Enough to bruise a bone.

Subject: RE: BS: The physics of a fall
From: Jean(eanjay)
Date: 19 Apr 07 - 03:59 PM

Per second per second is the same as per second squared.

Subject: RE: BS: The physics of a fall
From: TIA
Date: 19 Apr 07 - 04:08 PM

Total energy = kinetic + potential

=(1/2*m*v^2)+(m*g*h)

or

=1/2*m^2*v^2*g*h

where

m=mass
g=980 cm/s^2
h=height of point where fall began above step where fall ended
v=velocity of faller at point where fall began

Plug and chug for numerical answer.

It'll still hurt like hell.

Subject: RE: BS: The physics of a fall
From: Slag
Date: 19 Apr 07 - 04:28 PM

Right. Check your post. I think you omitted the second "per second,"

Subject: RE: BS: The physics of a fall
From: MMario
Date: 19 Apr 07 - 04:34 PM

g - 10 m/sec*sec to keep it in the terms posted

but the answer you want is that yes, the force would be spread through the tissues and cause damage outside of the site of actual impact.

Subject: RE: BS: The physics of a fall
From: catspaw49
Date: 19 Apr 07 - 04:35 PM

Did you go to a doc about this? Check for breaks or hairline fractures? That type of fall and the associated bruising might also bear a look at a deep vein thrombosis which can also cause clot problems........

Spaw

Subject: RE: BS: The physics of a fall
From: Rapparee
Date: 19 Apr 07 - 04:35 PM

Put ice on it. Keep it elevated, and for Crissakes, see a doctor!

Subject: RE: BS: The physics of a fall
From: Jean(eanjay)
Date: 19 Apr 07 - 04:39 PM

Slag, it was Amos' post I was referring to. He wrote 32 ft/sec per second.

Subject: RE: BS: The physics of a fall
From: Jean(eanjay)
Date: 19 Apr 07 - 04:43 PM

.....not that it really matters. I don't know why I mentioned it; I must be bored tonight!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 19 Apr 07 - 04:51 PM

Appreciate the defense.


A

Subject: RE: BS: The physics of a fall
From: Bee
Date: 19 Apr 07 - 05:03 PM

Ouch.

If you haven't seen a doctor, do - and again...ouch!

Subject: RE: BS: The physics of a fall
From: Wolfhound person
Date: 19 Apr 07 - 05:04 PM

Bruising is internal bleeding. You want to get it checked out *now*, and for goodness sake keep it up and rested. *Don't * overdo it or you'll risk all sorts of complications

I did something similar a few years back and now have a permanently torn thigh muscle. After 6 weeks I had to have a pint of excess and misplaced fluid drained from the injured area.

I don't do physics, though, sorry

Paws

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 19 Apr 07 - 05:09 PM

The ER docs were very nice - they are the ones who prescribed RICE (Rest, Ice, Compression, Elevation) - but I've come back to work where I sit a lot with my leg down. I asked about thrombisis and they said not to worry - but man, my calf is FILLED with decomposing blood. And it's crawling up my leg in the most glorious technicolor.

Hurt like I couldn't have imagined - but then stopped hurting, I continued my walk to dinner, had dinner - and then tried to get up again and literally could not walk.


Anyway, back to the physics - always let g=10 or your students hate you.
I'll try TIA's formula when I have more brains...

Subject: RE: BS: The physics of a fall
From: catspaw49
Date: 19 Apr 07 - 06:20 PM

No, not back to the physics, back to the doctor.   Don't let this go Myrrz.......I could tell you about sister Connie but it would take too long for all the details. Just go check back and let them evaluate what is happening now.

Spaw

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 19 Apr 07 - 06:43 PM

The others have done the physics but my (somewhat similar) experiences suggest to me that what you may be experiencing is usually called a subperiostial haematoma. A haematoma is basically a spectacular bruise. The periostium is the membrane surrounding the bone tissue, so a subperiostial haematoma is a bruise under the periostium.

Yours sounds more spectacular than most but RICE is the trick. If you do it repeatedly (as I did when training and competing in IV Judo many years ago; lots of vigourous ankle blocks that were more like batterings) the shin bone develops a rough feel. This was also a sign of tertiary syphyllis in times past but I've successfully avoided such parasites. And I can report that the roughness of the shin caused by repeated subperiostial haematomas gradually smoothes out again.

All the best.

Cheers, Rowan

Subject: RE: BS: The physics of a fall
From: leeneia
Date: 19 Apr 07 - 07:48 PM

"but I've come back to work where I sit a lot with my leg down."

Here's what to do, Mrrzy. Pretend that your employers FORBADE you to elevate your leg. If you are like most people, that will motivate you to elevate it, and it will get better faster.

Subject: RE: BS: The physics of a fall
From: Bill D
Date: 19 Apr 07 - 07:55 PM

.......(and be sure to pray a lot...*grin*)



take care.. and give up the trampoline lessons for awhile...

Subject: RE: BS: The physics of a fall
From: JennieG
Date: 19 Apr 07 - 08:26 PM

Ouch!

Plus what Bill D said about the trampoline lessons....and I would add tango lessons too.

Cheers
JennieG

Subject: RE: BS: The physics of a fall
From: TIA
Date: 20 Apr 07 - 09:30 AM

Other factors that would be important are:

The area of the bruise since stress is force per unit area. One would probably rather be hit with large (blunt) object rather than a pointy or sharp one of equal weight and acceleration.

Coefficient of restitution (or "give") of the step. A steel step with no "give" will hurt a lot more than a carpeted one.

Made for great mental entertainment thinking about fall physics on the train last night. Thanks for falling Mrrzy.

Subject: RE: BS: The physics of a fall
From: Amos
Date: 20 Apr 07 - 10:02 AM

Using TIA's formula:

m        85        kg
v        1.5        m/s
g        9.8        m/s/s
h        2        m
m^2        7225        
v^2        2.25        

m^2v^2gh        318622.5        
/2        159311.25 joules

or about 53Kjoules per square centimeter.


I think this is high. But I don't have time at the moment to track down the error.

A

Subject: RE: BS: The physics of a fall
From: MMario
Date: 20 Apr 07 - 10:07 AM

h would be smaller because it would calculate from the height of center of mass.

Subject: RE: BS: The physics of a fall
From: Amos
Date: 20 Apr 07 - 10:26 AM

OK, so 1 m instead of 2 m for "h", and you still get an awfully high number.


A

Subject: RE: BS: The physics of a fall
From: MMario
Date: 20 Apr 07 - 10:32 AM

well - it's concentrated. 3 square centimeters is probably less then 1 % of the area that normally supports that mass

Subject: RE: BS: The physics of a fall
From: Amos
Date: 20 Apr 07 - 10:50 AM

Actually, it is probably incorrect to compute all the impact as focusing on the point of contact. A lot of that energy is dissipated across the whole area of the accelerated mass whether it is still moving or had its own impact _after_ the ankle hit the stairs.

A

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 20 Apr 07 - 11:28 AM

Well, it sure FELT like the impact was focused! And I saw my regular doc today, one week later, and he said just to watch for infection if the little scrape riding like a flea on an elephant on top of the swelling gets red.
But he agreed with my theory that it was the lipostatic pressures as the energy whoomed around inside my leg that caused the huge swelling and bruising... so I'm wondering, if I were thin and still weighed this much, same fall, do you think it would have broken the bone? Never been so happy to be padded!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 20 Apr 07 - 08:04 PM

Helpful wonderful physicists, I have more data, and thus (of course! I'm a scientist) another question. Pretty please? Love you all!

Update: There is a large collection under my ankle that is newish, and obviously seeped from somewhere, so I took another look in the full-length mirror (rather than looking at my leg, you see; made me wonder if individual tigers know they're striped) and saw amazing wave-form patterns in the bruising that strongly support my blast-being-transferred-through-a-lipohydrostatic-medium theory. I can't draw in html so bear with me.

Recap: The impact site is on the front of my shin going top-o-centrically from the middle of the shin (in the vertical dimension) outwards and downwards about 5 cm, usually less than a cm wide and possibly slightly deeper and wider at the top. It has gone from a kind of skinned-knee-ish scrape to dark thick flat mostly numb stripe that looks for all the world as if it had had stitches, which it didn't. It sits on a little pillow of swelling whose bruising has now turned yellow, which makes it absolutely repulsive. The nurse actually called it Dreadful.

Anyway, the point is that I hit pretty much in parallel to the plane of the shinbones, at an angle that sent the blast inwards and upwards.

The greatest area of swelling, which still looks pretty bad, goes upward and inward from the impact site to the very top of my calf, and doesn't wrap around to the side or up into my knee.

The dark bruising on the inside of my left calf and around to the shin on that side, that seemed to me to go pretty much from above the knee to the ankle, turned out to go all the way to the sole of my foot but* - critical datum here- *is darker in thin stripes that are parallel to the impact scrape and equally spaced, like ripples in a pond. Of Mrr.

The huge and still very purple bruise in my popliteal region (relax - back of the knee, down you scoundrels) turns out to be counter-coup, the injury from the blast going right through me to the other side. You get this in brain injuries too - shake like a bowlful of jelly, we do, and our insides rattle around inside our outsides and whack against the other side - the other inside of our outside, that is. Ya folla?

The bruising that was creeping from my outer lower left (neither shin nor calf- what IS that part called?) up the outside of my thigh in a kind of arc around my knee joint also resoleved into parallel stripes going outward from the impact site. That is, what I was seeing as a vertical stripe of bruising (when standing up and my knee isn't bent) turns out to be a series of parellel-to-the-impact-area stripes that together comprise a vertical set of bruises running together in my perception.

I love data. They sure distract you from actuality when you want them to, without taking you out of reality at all!

OK, so, here's the next question: the stripes from the blast petered out in about, say, a half meter either side of the impact, anywhere the blast had a half-meter to travel in. When it didn't, as in directly through my leg across the knee from it, looks to have been the worst damaged after the shin itself. But now, can we verify our calculations of the blast strength?
And once it's in joules or something meaningful to you helpful physicists, can you translate that into either kilocalories (it was like your shin at 17 big macs in basically 0 seconds) or square meters of area cleared if you were in helpful rather than destructive demolitions?

Subject: RE: BS: The physics of a fall
From: folk1e
Date: 20 Apr 07 - 08:43 PM

The problem with the figures in previous posts is that whilst they "look" accurate they are not!
If you are going to take acceleration (due to gravity) it is only aplicable in a free fall situation. If you were to jump 2m in the air the acceleration would determine your speed when you "hit the floor"! As you were running when you "tripped" the acceleration would be reduced.
Your body mass did not stop when your knee came into contact with the step, but slowed as your body crumpled up.
Your arms would be flailing round and therefore alter the effective body mass.
As you came into contact with the step your shin absorbed some of the energy of the impact by compressing and bending.
Unfortunately the many forces involved quickly become so complex that an accurate figure is not attainable! If you doubt this you only have to look at slow motion video of bodily contacts, for example in the film "Rocky"! The body can change shape dramatically for short periods of time!
Still hurts though!!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 20 Apr 07 - 08:45 PM

I can't confront doing this problem. Every timne I think about it I flinch!! :D


A

Subject: RE: BS: The physics of a fall
From: Amos
Date: 20 Apr 07 - 08:52 PM

I don't think she needed a physicist to tell her it hurt.

A

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 20 Apr 07 - 09:20 PM

Sympathy is also gut.

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 20 Apr 07 - 11:59 PM

Mrrzy, "Sympathy!!!!!"

And some distractions?
The colourations you've described do indeed sound as though hydrostatic pressure waves were cruising through whatever soft tissue was there to take them. The parallel stripes probably indicate locations of particular muscles, which would be more likely than tendon to conduct pressure waves (tsunamis?) down into the foot and past the knee into the thigh.

I gace up on trying the physics for the reason outlined by folk1e. And I agree, it DOES hurt.
But it will go away and the colour transitions will take some time to complete.

Cheers, Rowan

Subject: RE: BS: The physics of a fall
From: kendall
Date: 21 Apr 07 - 08:51 AM

Just think how lucky you are. If you were elderly, it could have been your finish.

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 21 Apr 07 - 02:52 PM

Absolutely, Kendall! The luckiest I've probably been, if you want to look at it that way!
Not to mention it's a great story...

Subject: RE: BS: The physics of a fall
From: Slag
Date: 21 Apr 07 - 04:28 PM

All that pretty black, blue, purple, yellow brown and green(not gangrene)will migrate to the bottom of your foot and around the edge somewhat. What fun!

As long as you are doing physics, don't forget air resistance, the Coriolis effect, celestial gravitational alignments, tension strength of bone, tissues, etc. tension and tensile strength of the material encountered, any retrograde motion you were able to effect, if any. Good Luck!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 22 Apr 07 - 01:26 PM

The Coriolis effect must be why I was turning as I fell, LOL! Lessee - I'm in the northern hemisphere...
(better get off the painkillers soon, eh?)

Subject: RE: BS: The physics of a fall
From: TIA
Date: 22 Apr 07 - 11:08 PM

In which direction did they wrap the leg?

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 22 Apr 07 - 11:39 PM

Hee hee! I have to go flush now!

Subject: RE: BS: The physics of a fall
From: Stilly River Sage
Date: 23 Apr 07 - 06:57 PM

About 10 years ago I fell by tripping on a raised section of sidewalk, and landed smack on the front of my right knee and my hands so fast I was hardly aware I was falling until I landed. Hurt like hell, took ages to get over. I probably should have taken it to a doctor. Condolences to anyone with something as painful as that.

SRS

Subject: RE: BS: The physics of a fall
From: Naemanson
Date: 23 Apr 07 - 07:17 PM

I agree with all that's been said. You have my sympathy. I am just getting over corrective surgery on my wrist after a fall.

Maybe we should go back to just before the fall. What were you doing? Hurrying. Why? That's for you to consider. Result? Injury. Lesson? Don't run, don't hurry, stay calm, and let others take the falls.

Subject: RE: BS: The physics of a fall
From: Amos
Date: 23 Apr 07 - 08:05 PM

I think we'd all be mnuch happier if we went back before the Fall.

:D

A

Subject: RE: BS: The physics of a fall
From: Mr Happy
Date: 23 Apr 07 - 09:08 PM

What's a square second??

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 23 Apr 07 - 09:20 PM

Surely a square second is the untrendily conventional supporter of a duellist?

Subject: RE: BS: The physics of a fall
From: Mr Happy
Date: 23 Apr 07 - 09:25 PM

.........& if your ankle's affected, surely the calculation should be in foot pounds!!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 23 Apr 07 - 09:40 PM

I do wear hats, but that's toque, not torque.

Not hurrying, just going down the steps to go out to dinner with one of my twins. I was kinda tripping down the stairs like pretty Peggy-O, I guess!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 23 Apr 07 - 09:46 PM

A square second is an uninteresting young lady who... well, never mind that. I think you mean a second squared, which is a term used to describe a rate of change of velocity. Gravity accelerates things at 9.8 meters per second squared (i.e., 9,8 meters per second increase in velocity, for every second of fall under ideal conditions).


A

Subject: RE: BS: The physics of a fall
From: TIA
Date: 23 Apr 07 - 09:49 PM

a square second is a second per second or 1/second/second. A rate of change...a change of one second per one second of actual time.

Subject: RE: BS: The physics of a fall
From: The Fooles Troupe
Date: 23 Apr 07 - 10:02 PM

I once was struck on the forearm. The whole forearm swelled. I began to suffer anoxia - lack of adequate blood flow to the area. Any attempt to use the muscles for more than a few seconds resulted in excruciating pain to the point of blacking out if I bumped the arm, and lack of ability to sleep - even the doctor was unhelpful.

I immersed the whole forearm in ice water till it was completely numb - this eased the pain. I let it warm back to feeling again and repeated this cycle a few times - basically till I could not cope with the 'going to sleep and waking up again' of the nerve sensations.

This caused the swellng to abate - later discussions with those more experienced revealed that there must have been some obstruction to a vein that prevented the normal blood drainage from the limb - this meant that anoxia - lack of sufficent oxygen reaching the tissues - the pain was the cells complaining that they were 'dying'... :-)

The cold cycle caused something useful to happen to heal the problem - the cold can reduce swelling - and the reduction of swelling means that normal blood flow can occur. Once normal blood flow occurred as the arm warmed up, whatever the obstruction wsa to the blood flow was relieved.

Trust me this method DOES work - footballers etc do it all the time - but the complete numbing and rewarming process IS 'difficult to tolerate'.... :-)

When I did my AZSMF Sport Trainer course, I found out why it works... :-) or at least that it DOES so often that it is highly recommended if the swelling stays up for more than a day - some Aussie footballers made it into the media by sleeping on ice packs - thighs are difficult to get totally numb because that have massive noirmal blood flow and deep veins.


Robin

Subject: RE: BS: The physics of a fall
From: The Fooles Troupe
Date: 23 Apr 07 - 10:05 PM

"AZSMF Sport Trainer "

ASMF Sport Trainer - damn typos - no browser spellchecker in Linux Mozilla!

Subject: RE: BS: The physics of a fall
From: Stilly River Sage
Date: 23 Apr 07 - 10:40 PM

Maybe we should go back to just before the fall.

Amos, you're too quick, I saw that also. :)

This conversation could have taken a huge turn to the right with that remark!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 24 Apr 07 - 09:20 AM

LOL! And yes, I use a lot of ice. I'm back at work but doing a full day is very difficult... I can sit but then trying to get up again is a real pain.

Subject: RE: BS: The physics of a fall
From: The Fooles Troupe
Date: 24 Apr 07 - 08:35 PM

"I can sit but then trying to get up again is a real pain"

Me too - but I'm told that's just laziness.... :-P

Subject: RE: BS: The physics of a fall
From: GUEST,Rebecca
Date: 26 Apr 07 - 01:28 PM

I did the same thing last Friday! They took x-rays at the ER and told me that the swelling and bruising would begin to move down my leg due to gravity (yes, I sit at a desk all day at work, too) and let me tell you, by the time I get home at night, my right leg is twice the size of my left. It's been almost a week and seems to be getting worse instead of better... I guess it's another trip to the doc for me. GOOD LUCK HEALING! I feel your pain. I won't be wearing skirts or heels for a while!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 26 Apr 07 - 01:33 PM

No, no, wear skirts! i show my bruising off and nobody knocks into me...
yes, the swelling has reached my toes, now that it's been almost 2 weeks - not so much pain as pressure, now, though, so that's good...

Subject: RE: BS: The physics of a fall
From: GUEST,Rebecca
Date: 27 Apr 07 - 02:38 PM

Ha! That would be lovely! My right leg from the knee down is TWICE the size of the left! And the cut... and bruising? YUCK! =) Does anyone really want to see that? I do like the oohs and aahs when I lift my pantleg at work though, to show off my battle scars. I only told ONE person here at work about my fall (I fell at work while leaving last Friday at the end of the day, so I had to report it to HR and our legal department) and now everyone knows... so I know it's our lawyer who's been telling everyone! Nice, huh? I do enjoy the sympathy I get though when people see it. After a week, the pain is definitely less, but it's still as colorful and impressive as ever!

I'm glad you're feeling better. (And sorry I can't contribute "physics-ly". I barely made it through my 12th grade physics class! But we did get to go to an amusement park and calculate physic-y things on the rides that year... that was fun. LOL)

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 27 Apr 07 - 05:20 PM

Yes - 2 weeks ago today, and my foot still swells if I don't have it up all the time.
The bruising has reached the bottom of my foot...

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 04 May 07 - 08:53 PM

OK - anybody want to know the really really yucky continuing saga?

Subject: RE: BS: The physics of a fall
From: Amos
Date: 04 May 07 - 09:17 PM

Oh, please don't keep us hanging!! Do you still have a leg?


A

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 06 May 07 - 07:16 PM

Yes... for now!
Brace yourself...

The whole bottom leg was showing lots of bruising, turning the pretty colors of old bruises on the inner side and back, but the bruising on the outside (which went all the way down to the bottom of my foot) kept staying that dark blue of new bruise. That should have been clue # 1. Also, there was still a huge swelling where I had actually hit the step, with the little scrape on top having turned into a tadpole-shaped (sperm-shaped?) scab; if there started to be redness around it I'd put antibiotic ointment on it, and cover it. If I did that, the cover always ended up bloody, even though the scab itself wasn't bleeding. That should have been clue # 2.

So then, last weekend while at the Rally Against the Veto, I managed to fall again - onto some nice, soft, comfortable bricks - and on the exact same shin. Ouch. The swelling got even bigger, and the scab started bulging out a little. I'm OK, I go home, and I pick the teeniest tiniest bit on the tail end of the scab - and a squirt of dark blood comes out. I go to the bathroom to wash it off, and I guess the washcloth loosened the head end of the scab, and my leg practically EXPLODED. The whole swelling was apparently blood, under tremendous pressure. I mean, there were gobbets of black, goopy, dark bloody gobs all over the mirror, the far wall of the bathroom, the far end of the shower... it was the most amazing thing I've ever seen or experienced. The swelling vanished and I was left, after standing with my leg over the toilet while it lavaed out (making those horrible horror move squelching noises), looked like it was vomiting black goopy things - some of them came half-way out and if I helped, it would come out in blobbly chains of tissue and clot and wowie gross stuff. It was FASCINATING.

Anyway, I was left with no swelling, no scab, but a hole the diameter of my thumb that went through my skin all the way into the insides of my leg. And since the swelling had lifted the skin layer away from the rest of my insides, I could SEE for absolutely inches into my leg in all kinds of interesting directions... you could see the severed ends of things that looked like muscle, and things that looked like the big vein I probably busted in the original fall... it was wild.

So, back to the doctor, who says there is no way to repair something like that - I get to keep it covered with antibiotics and wrapped under pressure, and I'm taking oral antibiotics too, and I change the dressing thrice daily and with the pressure, now, the hole just goes through to the underlying tissue but there is no more great internal cavity (I could have put my whole hand into it if I could have gotten through the hole). And the bruising on the outside of my leg and foot is finally turning colors so I think there is no new bleeding going on.

And I'm probably going to miss float trip this year, since the chances are basically zero that the hole will have filled itself in by then, and I can't take showers (and trying to take a bath with one leg out of the tub is really hard on my back!)... we go down the New River every memorial day... rats!

But wowee. Really wowee. Thanks for letting me spew the info here too!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 06 May 07 - 09:48 PM

Great Gawdamighty, lady; that is the most vivid description of explosive putrescence I have ever had the honor of hearing!!

Do keep it dry and healing. Wow.


A

Subject: RE: BS: The physics of a fall
From: JennyO
Date: 07 May 07 - 12:04 AM

YIKES! That was - er - very colourful! Well, we were warned!

I wonder what would have happened it you hadn't had that second fall. It was probably fortunate that it happened. It sounds like something you are going to have to look after very carefully, so good luck with it!

While you are resting it - what about a song challenge? I have the unfortunate habit of writing bad bush-style poetry about my mishaps. It seems to make me feel better at the time, although sometimes it's hard to see the humour in these situations. I think yours has possibilities!

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 07 May 07 - 10:09 AM

Yes - homeopathy works! The second fall fixed the swelling from the first - kinda like the cartoon character who gets their memory back from the second blow to the head...

Ooh - song challenge - Great black gobs of greasy grimy Mrrzy leg?

And I'm not going to resist picking scabs any more. If I'd been picking this one instead of abstaining, I might have burst the dam a lot sooner... and prevented the lake from forming in the first place.

Thank you for letting me tell you about it! Everybody else is running away...

Subject: RE: BS: The physics of a fall
From: GUEST,Keinstein
Date: 08 May 07 - 04:54 AM

Two components: kinetic energy (walking speed) and potential energy (fall). Kinetic = 0.5mV^2 = 0.5 x 85 x (5000/3600)^2 = 82J. Assuming centre of gravity at 1m, PE = mgh = 85*9.81*1 = 834J. Total = 916J. that's not very much, is it, enough to raise 1kg of water 0.2 degrees?

But that's only a part of the problem. It's not difficult to absorb that much energy in your shin if you do it slowly. The real problem was that the ground broke your fall, and all that energy had to be absorbed in the time it took for the flesh of your shin to decelerate your moving body to a halt, or at least that portion of your body that halted before you sprawled out and your hands took the rest of the crash.

The extent of the bruising is probably caused by internal bleeding.

Subject: RE: BS: The physics of a fall
From: Mr Red
Date: 08 May 07 - 08:04 AM

no time to read all above - but if you were rotated in the fall some energy is transferred to pole moment of inertia. If you didn't break a bone most of the enrgy would have been transferred. Bones - particularly old bones - don't bend - especially round acute corners. You may still have bone damage - local crushing which will be lumpy even after the swelling/cushion subsides. But compared to the other possibilities that is a small problem.

Arnica is good at reducing haemoragging but not on broken skin.

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 08 May 07 - 07:33 PM

All bruising is aging (coloring) nicely, thank you. The hole is still quite, well, whole!

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 08 May 07 - 11:09 PM

A comely young lassie named Mrrzy
took a fall that was really a doozie;
while the bruising has healed,
the hole hasn't sealed
and its contents have made us all woozy.

Cheers (and best wishes), Rowan

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 09 May 07 - 09:22 AM

LOL!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 09 May 07 - 10:16 AM

Rowan:

How did you figure out how to pronounce "Mrrzy"? Or did you just use your poetic license?


A

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 09 May 07 - 12:09 PM

It actually is pronounced like the Mersey, of ferry fame. But that's OK! It WAS a doozie!

Subject: RE: BS: The physics of a fall
From: Amos
Date: 09 May 07 - 02:09 PM

Mercy on Mrrzy,
Who tripped on a stair,
Who staggered and stumbled,
On the concrete edge there.
Her poor leg is swollen
And purple and green
The yewgliest Owie
That we've ever seen!
She cannot go dancing
On the staircase from hell,
So mercy on Mrrzy,
Let us hope she gets well.

Meriwether Phogbottum III
Doggerel from Northwestern Climes
Gravite, Masse, and Fource, eds.
Sheboygan, 1967

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 09 May 07 - 06:11 PM

Amos, it was poetic licence combined with an Oz comprehension of possible accents.

Plus the fact that I thought a haiku might be too difficult to balance. All I could come up with was

She tripped down the stairs;
her shin flew, banged, then bruised black.
Dead blood left its hole.

Cheers, Rowan

Subject: RE: BS: The physics of a fall
From: Amos
Date: 09 May 07 - 06:16 PM

Feminine leg meets
Stone staircase
Gravity always wins.

A

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 09 May 07 - 06:50 PM

Nicely put, Amos

Subject: RE: BS: The physics of a fall
From: Stilly River Sage
Date: 09 May 07 - 08:18 PM

Wow. For as gorey as that sounded, it also sounded like the relief was tremendous.

   / / / > ~ ~ ^{. . .} . . @

: : : : - - - - - _{@ - - - -} . . @

    ~ ~ ~ ~ ~ . . . @   @   @ @@@


html blood and gore is difficult. Poetry does seem to be a better answer.

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 09 May 07 - 09:26 PM

Ooh, very well html'd! A little more spray, perhaps?

Yeah - but I gotta say the hole is showing no signs of closing... I hope I wake up one morning suddenly with my outer integument contiguous again! (Name that reference!)

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 10 May 07 - 03:42 AM

I suspect you not only want your outer integument contiguous but you want it continuous. Do take care.

Cheers, Rowan

Subject: RE: BS: The physics of a fall
From: Amos
Date: 10 May 07 - 09:59 AM

The reference is clearly to The Perianth and the Taxonomic Affinities of Eucalyptus Cloeziana by LD Pryor, LAS Johnson, MI Whitecross and DJ McGillivray.

A

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 10 May 07 - 07:00 PM

Garn, Amos! You're having us all on. You didn't read that paper, or you wouldn't have capitalised the specific epithet. And you forgot that, in italicised text like book titles, scientific binomials are not italicised.

CHeers, Rowan

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 13 Jun 07 - 02:06 PM

Sorry - it's Star Trek. Some alien or other, describing humans (I liked the ones who called us Ugly Bags Of Mostly Water better)...

Anyway, update - hole still goes all the way through, and here we are 2 whole months later. No more swelling or bruising but I am missing going swimming! I don't know if it will ever close since the edges are healed...

Subject: RE: BS: The physics of a fall
From: Ebbie
Date: 13 Jun 07 - 02:19 PM

Mrrzy, I'm surprised that the hole wasn't packed. I've seen two instances of 'hole-itis' and in both cases the doctors packed it, a dressing that had to be changed every day or two. In both cases
(the people are friends or relatives of mine) the hole did eventually fill in, although in my sister's case there is a definite dimple there.

I know a little about the relief- years ago I dropped a building block on my big toe. After a few days my foot throbbed so badly that I took a needle to a spot under the nail and whooooosh...

Subject: RE: BS: The physics of a fall
From: Rowan
Date: 13 Jun 07 - 06:27 PM

Fill us in, Mrrzy. Has it filled in yet?

Cheers, Rowan

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 13 Jun 07 - 08:56 PM

Hee hee - it's just very small, now, but it still leaks interstitial fluids if pressed, so I know it's still all the way through.
I was surprised they didn't pack it, too, but they had me cover it and goop it with that extremely expensive extra-strong antibiotics - probably caused a whole new species!

Subject: RE: BS: The physics of a fall
From: Sorcha
Date: 13 Jun 07 - 10:16 PM

Mrz, here is something to try that can't hurt I don't think. See if YOU can pack the wound with plain granulated sugar. Cover both sides. Irrigate/flush if you can every day and re pack.

Honest, sugar is what is used for those nasty spider bites that rot out and leave holes. It is what the Dr told my mom to use when she was bitten by a brown recluse/fiddle back.

Now, if you can't irrigate it, I wouldn't reccomend trying this. God knows what rotten sugar might do, but you could ask your Dr? It might just melt away.....

Subject: RE: BS: The physics of a fall
From: Mrrzy
Date: 14 Jun 07 - 11:10 AM

I don't think I can irrigate it - i really have to press to get it to leak, now. But I'll ask - that sounds intriguing. What did you mean by "both sides" though - the inside and the out?