Archery Ballistics

[RDU Neil]

There is a ton of information on bullet balistics, penetration, balistic gel tests for various rounds/loads, etc.

Is there anything on arrows... specifically on the unique damage to a human body done by an arrow? I know a four inch penetration through armor was usually considered a "kill" and not just a wound... but I'm thinking that was due more to poor medical aid rather than "insta-kill."

What I'm interested in is the kind of damage an arrow (think broadhead hunting tip or the long, pointed pile arrow as two main types of damage). How does penetration and damage compare to say, a 9mm round? What is the damage done trying to remove the arrow (sans silk shirt mongol style). What would be an appropriate damage/mod for a character trying to act with a sharp stick imbedded in them?

Basically, I'm trying to figure out some unique rules for arrow damage that would make them "feel" different than bullets. Don't worry about cost or build... just effect...

Like "Take 1d6 NND K when trying to remove the arrow" or "take 1 pip NND K if any action is taken while arrow is still imbedded, depending on hit location" etc.

Also, I'm assuming most soft body armor (no plate) will be like butter to a high velocity broadhead or pile arrow.

Any experts out there?

Thanks in advance

[Talon]

Not an expert, but I recall from past discussions that arrows do far more damage than their momentum / kinetic energy would indicate (especially when comparing to the energy in bullets).

I used to have a link to a study which showed that destroyed tissue was the key factor in wound severity -- bullets would destroy some tissue and "compress" a lot more (which would recover fairly quickly), while an arrow would not compress anything but would slice through quite a bit. Alas, the link went dead a long time ago.

[RDU Neil]

Not an expert, but I recall from past discussions that arrows do far more damage than their momentum / kinetic energy would indicate (especially when comparing to the energy in bullets).

I used to have a link to a study which showed that destroyed tissue was the key factor in wound severity -- bullets would destroy some tissue and "compress" a lot more (which would recover fairly quickly), while an arrow would not compress anything but would slice through quite a bit. Alas, the link went dead a long time ago.

This makes sense, as it is likely the arrow will transfer nearly every last bit of it's energy to the target, has a twisting/cutting head, and more mass in an arrow than most bullets.

While I'm comfortable with an arrow doing more damage than a pistol round (in most cases) I wonder about rifle rounds. The considerably higher velocity of a rifle round seems to me to greatly outgun even a heavy arrow fired from a powerful compound bow. Still, that is a guess, not based on any facts.

It is those facts I'm looking for.

Hmmm... maybe hunting has some resources. Deer get shot with bows and AK-47s all the time. How do those wounds and damage stack up, I wonder?

[bigdamnhero]

No claims to expert status here either. There have got to be some good bowhunting forums out there somewhere, and there must be some discussion of arrow damage. (You don’t have to tell them you’re doing gamer research!)


How does penetration and damage compare to say, a 9mm round?
...<snip>
Also, I'm assuming most soft body armor (no plate) will be like butter to a high velocity broadhead or pile arrow.
As I understand it, arrow penetration (through armor) is significantly less than bullet penetration. A "high velocity" arrow is not comparable to a high velocity bullet; the KE involved is like an order of magnitude less IIRC. And from talking to people that have actually tried it, my understanding is that a decent Kevlar vest will stop any arrow you can shoot at it.

Comparing damage is a little like comparing apples to oranges, because arrows and bullets do damage so differently. Bullets punch a hole through you, shatter any bone they might hit, and generally continue on out the opposite side; the main immediate damage they do is the shock from all the tissue compression. Arrows cause far less compression, and generally won’t penetrate as far; they can break bones, but don’t have the KE to propel bone fragments enough to cause additional damage. OTOH, a broadhead is significantly wider than a bullet and the rotation when it hits the target will do even more damage (bullets rotate too, of course, but they don’t have flanges). So it seems to me that while an arrow wound may be shallower than a bullet wound, the arrow wound could be messier.

So in game terms, I would be inclined to leave the damage levels about where 5ER has them, but give them Reduced Penetration (vs modern armor). Possibly a lower STUN Modifier, to reflect less shock from compression? Also, the shallower, messier wound might bleed more?


What is the damage done trying to remove the arrow (sans silk shirt mongol style). What would be an appropriate damage/mod for a character trying to act with a sharp stick imbedded in them?
I think these type of things are the key to making arrows “feel” different than bullets – the fact that you now have 18-24” of wood (or carbon or whatever) embedded in your chest. Off the top of my head, I would allow anyone removing an arrow to attempt a Medic Roll. If they make it, no additional damage; if they fail it they inflict an additional pip of BODY, NND. (Realistically, it might be more than that, but for game purposes 1 point is probably sufficient.)

As to penalties/damage from moving with an arrow stuck in you… I like your idea, but I’m not sure how best to implement it. Maybe require an EGO roll to take any action that involves moving that body part? Additional damage sounds realistic, but I might be inclined to make it NND STUN to reflect the pain factor, rather than it doing additional BODY damage. I’m making this up as I go here.

Oh, one other thing I have used in the past in modern games is that getting hit with an arrow gives an automatic +1d6 PRE Attack bonus just for the weirdness factor: “I’ve been shot by a freakin’ arrow? What’s up with that!?”

[bigdamnhero]

Simul-posting! :D

This makes sense, as it is likely the arrow will transfer nearly every last bit of it's energy to the target, has a twisting/cutting head, and more mass in an arrow than most bullets.
I suspect you're wrong here. Mass isn't nearly as important as velocity and bullets are an order of magnitude faster than arrows. But then I don't have a lot of data to back my position either. :o


While I'm comfortable with an arrow doing more damage than a pistol round (in most cases) I wonder about rifle rounds. The considerably higher velocity of a rifle round seems to me to greatly outgun even a heavy arrow fired from a powerful compound bow.
Rifle bullets are an order of magnitude above pistol bullets. No comparison there.


Still, that is a guess, not based on any facts.

It is those facts I'm looking for.
Yeah, I'd love to see some actual data myself. I could be wrong, of course. (Wouldn't be the first time.)

[bigdamnhero]

Aha! Found a good article on arrow damage:

http://www.buckmasters.com/buckmasters_links/Classic_Buckmasters/articles/SharpFactor.html


First, one must realize that game animals shot with arrows die from blood loss or hemorrhaging. Arrows, unlike bullets, have relatively little foot pounds of impact on big game animals.

My 80-pound compound bow delivers a 660-grain hunting arrow, leaving the string at 245 fps, with about 88 foot pounds of energy. Compare that with a .270 Winchester, 130-grain bullet leaving the muzzle at 3,100 fps and developing well over 2,500 foot pounds of energy. When you compare 88 foot pounds to 2,500-plus foot pounds, it’s easy to see why the impact of a hunting arrow means virtually nothing in terms of lethal impact on big game. A firearm relies on tissue damage and hydrostatic shock created by bullet impact to dispatch an animal. There just isn’t enough “oomph” in an arrow to do that.

In bowhunting, it’s all about the broadhead. It must slice cleanly with little or no bruising or tearing of the tissue. In very simplified terms, when a razor-sharp blade slices living tissue (muscle and/or organs) without bruising or tearing the tissue it has sliced, the brain fails to initiate the process which causes blood coagulation, resulting in extreme hemorrhaging.

The faster the hemorrhaging, the faster the oxygen supply (which is carried in the blood) is deprived from the brain, rendering the animal unconscious. Most animals taken with bow and arrow fall to the ground unconscious before death actually occurs. So, for bowhunters, the object is to create massive hemorrhaging with a razor-sharp broadhead. The sharper the broadhead, the quicker the animal will be dispatched.

[And here I thought I was going to get some work work done today - silly ol' me.] ;)

[bigdamnhero]

One more, then I have to get back to working on stuff they pay me to work on...

http://www.neurosurgery.org/sections/tr/guidelines/introductionandmethodology.pdf


Lower velocity sharp projectiles, such as arrows (120–250 ft/s [36–76 m/s]), wooden sticks, knives, and pencils create a track of primary tissue damage without substantial bruising or blunt tearing of surrounding tissue. In contrast, higher velocity projectiles result in a more complex wounding pattern. An impact shock wave precedes the projectile. This sonic wave is very brief (2
s) and does not contribute substantially to tissue destruction. As the projectile penetrates brain tissue, it crushes tissue in its path, creating a permanent track of tissue injury. Higher velocity projectiles will impart an additional temporary cavitation effect in their wake, which is a velocity-related phenomenon. This results from the transmission of the kinetic energy of the projectile to the surrounding tissue, thus rapidly compressing it tangentially from the primary track. After the cavity expands to its maximum size, it starts to collapse under negative pressure and can suck in external debris. This cavity will then often undergo smaller expansions and contractions of diminishing amplitude. In relatively inelastic tissue, such as the brain, this results in a track of injury often 10 to 20 times the size of the offending projectile.
<snip>
For these reasons, a .45 automatic pistol (muzzle velocity of 869 ft/s [265 m/s] and a short round-nosed projectile with little yaw) will create a very small temporary cavity. Conversely, a 7.62-mm rifle (muzzle velocity 2,830 ft/s [863 m/s] and a long, sharp nose with maximum yaw) will create a very large temporary cavity.

[Thia Halmades]

So... you could build your arrows as CON Drains, or with CON Drain effects tied to them for 'bleed,' Heals at the Rate Body Heals, and so on. That would represent the ability of the weapon to bleed someone out, rather than doing straight damage.

It's a more complicated model, but it seems to accurately reflect what the man with the brain is saying.

[bigdamnhero]

And from talking to people that have actually tried it, my understanding is that a decent Kevlar vest will stop any arrow you can shoot at it.
For what it's worth, Wikipedia (http://en.wikipedia.org/wiki/Bulletproof_vest) says I'm wrong: :eek:

Most vests offer little protection against arrows, ice picks, or stabbing knife blows. As the force is concentrated in a relatively small area with such bladed weapons, the tip of the object can push through the weave of most bullet-resistant fabrics. Specially-designed vests are available that can provide protection against bladed weapons, and sharp objects; they are often used in prison-guard vests. There are a variety of strategies to achieve stab and slash protection. Some materials like Dyneema do offer considerable protection against these types of threats. This is important for the safety of law enforcement and prison guard personnel.
I know the vest used in the test I mentioned above was a fairly expensive one (an FBI tactical vest, without plates). So maybe it would be more accurate to say that most high-end vests can stop arrows? In game terms: Reduced Penetration Only Against Vests Without Stab/Slash Hardening? Sorry to complicate matters further...

[Yansuf]

For what it's worth, Wikipedia (http://en.wikipedia.org/wiki/Bulletproof_vest) says I'm wrong: :eek:

I know the vest used in the test I mentioned above was a fairly expensive one (an FBI tactical vest, without plates). So maybe it would be more accurate to say that most high-end vests can stop arrows? In game terms: Reduced Penetration Only Against Vests Without Stab/Slash Hardening? Sorry to complicate matters further...

Modern fiber (kevlar, spectra, etc.) armor does not work well against arrows and knives, I don't know why. And I don't think anyone else does either; I have heard many conflicting answers. Some are very reasonable, but I don't believe anyone knows if they are right. (BTW, my PhD is in engineering.)

Based on historical evidence, some old fashioned soft armor did work well against arrows. Gambesons were widely used by the Crusaders and troops of the Kingdoms of Outremer, and were very good at stopping arrows, based on historical accounts. A gambeson is basically a very thick quilt.

I can say that the question of penetration depends not only on the energy of the projectile, but also on how much energy goes into the target and how much is used to deform the projectile. Based on my experience in the SCA with bows and crossbows, crossbow bolts penetrate much better than arrows for the same "muzzle energy." I believe that this is due to the energy lost in "flexing" the arrow, but I have never tried to test this, so it's just a guess.

[Remjin]

I know the vest used in the test I mentioned above was a fairly expensive one (an FBI tactical vest, without plates). So maybe it would be more accurate to say that most high-end vests can stop arrows? In game terms: Reduced Penetration Only Against Vests Without Stab/Slash Hardening? Sorry to complicate matters further...

Vests usually come in levels... from I to IIIA with advancing levels of protection. When I was looking to purchase one (my line or work doesn't require it, but its a good idea, and the cost was prohibitive so I didn't get one) they don't mention arrows and such on the list of things it protects against. :D There are separate vests, called stab vests, that are worn by corrections officers for that sort of thing.

Just my 2 cents...

[bigdamnhero]

Vests usually come in levels... from I to IIIA with advancing levels of protection. When I was looking to purchase one (my line or work doesn't require it, but its a good idea, and the cost was prohibitive so I didn't get one) they don't mention arrows and such on the list of things it protects against. :D There are separate vests, called stab vests, that are worn by corrections officers for that sort of thing.
Right. Don't remember the rating of the tac vest I mentioned, I remembered that it had stab/slash protection, but I forgot that wasn't "standard-issue."

So in game terms, would knives & arrows be considered AP (only vs Kevlar-type armor), unless that armor was bought with Hardened (only vs knives/arrows)?

[Yansuf]

Right. Don't remember the rating of the tac vest I mentioned, I remembered that it had stab/slash protection, but I forgot that wasn't "standard-issue."

So in game terms, would knives & arrows be considered AP (only vs Kevlar-type armor), unless that armor was bought with Hardened (only vs knives/arrows)?

I think that it would be more appropriate to take a limitation on the armor, half effect (or less) vs cutting and stabbing weapons. That could be a -1/2 or even a -1 limitation.

[Remjin]

Or a nice medium of -3/4 =)

I'd say it would depend on the type of game you're playing... in a game with knives/swords/arrows as being more prevalent it would be a bigger disadvantage versus a game where guns or energy blasts were more prevalent.

[Captain Obvious]

Modern fiber (kevlar, spectra, etc.) armor does not work well against arrows and knives, I don't know why. And I don't think anyone else does either; I have heard many conflicting answers. Some are very reasonable, but I don't believe anyone knows if they are right. (BTW, my PhD is in engineering.)

I haven't heard any conflicting answers. The answer I have heard is that arrows and knives concentrate their energy in a much smaller area than a bullet, giving them actually more energy per unit area.

[Yansuf]

I haven't heard any conflicting answers. The answer I have heard is that arrows and knives concentrate their energy in a much smaller area than a bullet, giving them actually more energy per unit area.

That is not true.
Basically, Kevlar and similar materials can be cut fairly easily.

[RDU Neil]

Since I'm needing these ideas for a game where equipment is "free" the limitation amount isn't that big a deal.

I will likely play up that "soft armors" i.e. standard bullet-proof-vests... without plates... would be 1/2 vs. knives/arrows, etc. Stab vests are unique and would provide full defense vs. knives/arrows... how they do vs. bullets, I have no idea.

As to a method of differentiating bullet damage from arrow damage... I'll probably allow arrows a couple of basic effects.

1) "There's a sharp stick imbedded in me" effect: 50% chance of 1d6 NND does body damage if action is taken with arrow still stuck in... judgment based on hit location and action taken. Ex: Throw a punch with arrow in arm... likely chance of more damage. Ex 2: Simply walking with arrow in arm... no chance of more damage.

2) "Wow... that's a lot of blood" effect: CON roll when hit with arrow. Missed roll, brain did not register shock and is not reducing blood flow... BODY loss of 1 pt per round on 11 or less roll until successful removal and paramedics roll.

3) "Should we take it out or leave it in?" effect: Removing an arrow without a combat paramec roll will do NND Killing Damage does body and can activate the bleeding effect.

Those basic house rules should make arrows "feel" different than bullets in most cases.

I've created similar "blow through" type house rules for hv/rifle rounds vs. targets that make heavy weapons do cool stuff vs. light or no armored bodies and shoot right through low defense walls like drywall and such.

Thanks everyone for your input.

[bigdamnhero]

I will likely play up that "soft armors" i.e. standard bullet-proof-vests... without plates... would be 1/2 vs. knives/arrows, etc.
Yeah, making it a Lim of the armor makes more sense than making it an Adv of the arrows (as I originally suggested).


Stab vests are unique and would provide full defense vs. knives/arrows... how they do vs. bullets, I have no idea.
I was under the impression that they act as normal vs. bullets. But then, I'm the guy who forgot normal vests didn't stop knives in the first place, so don't listen to me. :o


As to a method of differentiating bullet damage from arrow damage... I'll probably allow arrows a couple of basic effects.
I like these! I hadn't actually written any of my own rules down yet, so I'll just critique yours: ;)


1) "There's a sharp stick imbedded in me" effect: 50% chance of 1d6 NND does body damage if action is taken with arrow still stuck in... judgment based on hit location and action taken.
I might be inclined to make this based on a CON roll rather than just a flat 50% chance; not sure it makes any more sense in terms of realism, but I like tying it to a characteristic. And depending on how deadly I wanted to be, I might leave out the "Does Body" part and make it just about the pain. YMMV.


2) "Wow... that's a lot of blood" effect: CON roll when hit with arrow. Missed roll, brain did not register shock and is not reducing blood flow... BODY loss of 1 pt per round on 11 or less roll until successful removal and paramedics roll.
I was thinking of just using the standard bleeding rules, but treating arrow wounds as one level more severe on the Bleeding table. But if you're looking for something more lethal, that'll work fine.


3) "Should we take it out or leave it in?" effect: Removing an arrow without a combat paramec roll will do NND Killing Damage does body and can activate the bleeding effect.
Good. How much Body damage - 1 pip? If using the standard bleeding rules, maybe a failed Medic roll makes the wound one level more severe on the table?


I've created similar "blow through" type house rules for hv/rifle rounds vs. targets that make heavy weapons do cool stuff vs. light or no armored bodies and shoot right through low defense walls like drywall and such.
Veering off-topic, but... We tried something similar to this once (treated all rifles as having one level of AP), but found it resulted in a higher mortality level than we wanted. Have you experienced this, and if so how did you deal with it? Or are you just more comfortable than I am with a high mortality level?

[RDU Neil]

I might be inclined to make this based on a CON roll rather than just a flat 50% chance; not sure it makes any more sense in terms of realism, but I like tying it to a characteristic. And depending on how deadly I wanted to be, I might leave out the "Does Body" part and make it just about the pain. YMMV.

To get really crunchy, I'd probably make off-hand rulings based on the hit location for what kind of damage is done. A torso shot might not cause a ton of pain, but movement could cut something really important (high body, low stun type of attack) while an arrow stuck in the leg could grate against bone and be excrutiatingly painful without really life threatening (high stun, low body type of attack)

As a GM, I'm comfortable making these rules up on the fly, but sometimes the players want to have things written out ahead of time so they can know what to expect.


I was thinking of just using the standard bleeding rules, but treating arrow wounds as one level more severe on the Bleeding table. But if you're looking for something more lethal, that'll work fine.

I should probably look at 5th Ed bleeding rules... I really haven't done that in a while because old bleeding rules were pretty lousy. Also... to be clear... each round a 11- would have to be rolled, so 47% of the time (IIRC) no blood loss would occur. Basically have to fail an initial CON roll... then also roll 11- every round to continue to bleed. Shouldn't be TOO lethal... except when it is, and that is cool with me.


Good. How much Body damage - 1 pip? If using the standard bleeding rules, maybe a failed Medic roll makes the wound one level more severe on the table?

In my style of GMing... I'd base the damage on how badly they missed the paramedics roll (since everyone gets it at 8- ) Barely miss it... maybe a pip and some stun. Miss it a lot, roll a d6 and bleeding... roll an 18 on paramedics, likely do as much damage as if he was shot all over again. That kind of thing.

This is what I love about Hero. Especially when you don't have to worry about "costing" an ability... the basic mechanics and rules of the game can be used in a lot of flexible ways to simulate very specific stuff in game.


Veering off-topic, but... We tried something similar to this once (treated all rifles as having one level of AP), but found it resulted in a higher mortality level than we wanted. Have you experienced this, and if so how did you deal with it? Or are you just more comfortable than I am with a high mortality level?

Depending on the round, I usually give rifles "Light AP" This works because I use alternate AP rules. No "halving" of defense... but Body of AP attack subtract from non-hardened defense. Ex: 7 body on 2d6 AP attack... -7 to non-hardened resistant defenses of target. Will blow through most light body armor.

This way of doing AP is more flexible, because I can apply the AP to only SOME of the dice of an attack. For "Light AP" on a 7.62 round... normally 2d6+1K... I'd say 1d6 of that was AP. So roll a 4 & 3... a 3 on the AP die +1 = 8 Body/3 AP... will blow through a second chance vest... but a heavier vest would still have some defense. This tends to work REALLY well in giving different rounds different "feel."

Adding plates to Body armor not only ups the defense, but turns that defense into hardened in many cases. Thus you can have the effect of assault rifles chewing up light/no armor guys... but suddenly being stopped cold by Level IV vests... all within a tight damage range of 1 1/2d6 - 3d6 Killing. (Essentially, my mods are driven by the fact that compacted ranges of damage at these levels means there needs to be other ways of differentiating attacks than more or less dice.)

Yeah... off topic, but fun to talk about. :thumbup:

[bigdamnhero]

I should probably look at 5th Ed bleeding rules... I really haven't done that in a while because old bleeding rules were pretty lousy.
They haven't changed much (if at all) from 4th Ed. I'm okay with them myself, but if you didn't like them before odds are you still won't.


In my style of GMing... I'd base the damage on how badly they missed the paramedics roll (since everyone gets it at 8- ) Barely miss it... maybe a pip and some stun. Miss it a lot, roll a d6 and bleeding... roll an 18 on paramedics, likely do as much damage as if he was shot all over again. That kind of thing.
I think I'd probably just cap it at 1 pip, but that's me.


This is what I love about Hero. Especially when you don't have to worry about "costing" an ability... the basic mechanics and rules of the game can be used in a lot of flexible ways to simulate very specific stuff in game.
Amen. :thumbup:


Depending on the round, I usually give rifles "Light AP" This works because I use alternate AP rules. No "halving" of defense... but Body of AP attack subtract from non-hardened defense. Ex: 7 body on 2d6 AP attack... -7 to non-hardened resistant defenses of target. Will blow through most light body armor.
Your ideas are intriguing to me and I wish to subscribe to your newsletter. :D

Seriously, that's probably crunchier than I like to get in most of my games, but for really gritty, gun-heavy campaigns it's not a bad approach.

[RDU Neil]

Your ideas are intriguing to me and I wish to subscribe to your newsletter. :D

Seriously, that's probably crunchier than I like to get in most of my games, but for really gritty, gun-heavy campaigns it's not a bad approach.

Thanks... and don't get me wrong... I'm not trying to imply this level of "crunch" should be universal in application. I would never approach this kind of detail in a supers game or even most "cinematic" style games. For the more "realistic" games though... where combat tends to be just guns/knives/kicks & punches... the generic damage feel of Hero can become repetitive. Since such games (in my experience) are not about having characters buy "powers" that are built to simulate effect... it is much easier to have campaign rules that are in effect for everyone to help simulate the detailed nuance of different guns, slashing vs. stabbing vs. impact damage... the nuance of bullets... the vast differences of explosives vs. high velocity mass, etc.

Hero can actually handle most of this kind of crunchy task resolution... it just takes a lot of thought ahead of time on how much you want to deconstruct things... and how much is just "Take 6 Body, 18 Stun. Next!"

[Krieghandt]

location, location, location. arrows that dont hit organs or major blood vessles are just painful areas of potential infection. Another known effect is that major muscle groups that have arrows, fencing blades, pencils, etc have a good chance of "shutting down" about 45 seconds after being damaged. I think the biggest reason of arrow penetration of kevlar is speed. bullets try to strecht and snap kevlar strands, which is 100 % of its strength, while slower objects try to move the weave aside. Carbon fibers are only 10% strength vs. sheer stresses.
just some observations
Krieghandt

[Bismark]

Another thing to bear in mind with archery is that the payload matters as much as the launcher: light, bendy arrows (as used by a lot of steppe/eastern archers throughout history) are particularly bad at penetrating almost any rigid armour (and decent mail, or padded armour for that matter) at above short range, even when equipped with small AP-style heads (which they often were, to conserve valuable metal) and fired from an obscenely powerful composite bow. They will just shatter against iron/steel plate armour at short range. Load the same bow with a rigid, heavier arrow and see the difference...

A side effect of this sort of thing is that light arrows are actually far too effective at stunning people wearing helmets in HERO - if the arrow does not penetrate the helmet, it should be a maximum of 1 STUN done as the arrow has neither the momentum nor the kinetic energy to cause appreciable blunt trauma in that circumstance (time to ignore the 'x5 STUN before armour' for head shots).

In fact non-penetrating arrows will only cause noticeable impact effects if they are close-range or point-blank hits with heavy arrows (longbow arrows, Mongol AP specials, etc.).

I encounter the above factors all the time in my FH campaign; eventually I decided that unless it was a point-blank hit, only BODY that penetrated the armour counted for STUN determination purposes.

[Markdoc]

Couple o' points:

First off the myth that arrow wounds are in some mystical way different from bullet wounds is, well, a myth. This kind of thing:

"In bowhunting, it’s all about the broadhead. It must slice cleanly with little or no bruising or tearing of the tissue. In very simplified terms, when a razor-sharp blade slices living tissue (muscle and/or organs) without bruising or tearing the tissue it has sliced, the brain fails to initiate the process which causes blood coagulation, resulting in extreme hemorrhaging."

is just fantasy. The brain has nothing (that's zip, zero, nada, not a sausage) to do with blood clotting, which is a chemical reaction caused by exposure to material released by damaged cells or to changes in ambient oxygen. Slashing and stab wounds do bleed a lot. Guess what? Bullet wounds bleed like billy-o, too. What determines how much you bleed is the size and number of blood vessels opened - not how they were opened.

The short version is that wounds - all wounds - kill in one or two ways. One is if the missile hits something vital (brain, heart, major nerve). The other is bleeding. All this stuff about hydrostatic shock, extreme hemorrhaging, etc is hooey, made to fill up magazine columns.

Arrows are less likely to be rapidly lethal than bullets (even pistol bullets) because they have less penetration and therefore are less likely to hit something vital (there's a reason the gun replaced the bow...). All of your vital bits are pretty well buried. However, a broadhead arrow may actually cause more bleeding than a pistol bullet simply because of the size of the head - it gives you a greater chance of slashing a major blood vessel. In other words, it makes a bigger hole. A rifle bullet will make a skinnier hole, but odds are, it will be just as big, or bigger, since it's a *long* skinny hole - and it's more likley to be lethal since it gets to where your important stuff is kept.

So to sum up, rifle bullets are more likely to kill (I think that's covered by the increased DC already), pistol bullets more likely to wound and arrows *may* cause more bleeding (so you might want to decrease the chance of bleeding stopping for rifle and arrow wounds if you use the bleeding rules).

I'm not sure that the whole "removing the arrow" thing adds much in terms of realism - moving with a bullet inside you is damn painful too, and will also cause damage: in real life, any medical attention should involve getting that out as fast as is safely possible. But if it adds to the feel, go for it.

I can't really say anthing about kevlar, since I have never seen anyone shot wearing kevlar - either with a gun *or* a bow :D

But the other thing to consider is that a bow is as silent as a silenced pistol, so that can addto the freaky factor - if there's much background noise, the arrow can appear as if from nowhere.

cheers, Mark

[Thrakazog]

*looks around*


I think I'll just stay with the rules as given.

:p

[Markdoc]

*looks around*


I think I'll just stay with the rules as given.

:p

Me too: I don't actually WANT realistic combat in my games, even those that are "gritty". All I want are rules that encourage people to behave rationally (like seeking cover when being shot at).

Still, if other pople wish more detail - it's Hero system: detail away!

cheers, Mark

[Starwolf]

Sorry to jump in this late in the conversation. I can't quote hard science, but I am an avid hunter both with rifle and bow. The damage done is very different. For rifles what knocks an animal down is shock. When a bullet penetrates in addition to the hole, it makes tissue expand as it passes through which then collapses behind the bullet (Or fragments if the bullet splinters). Each channel causes this hydrostatic shock. The animal drops from this trauma. This is why you NEVER chase a wounded animal, if you get the adrenaline flowing the beast will run forever before succumbing. If you take the shot then move up slowly, usually the animal will move off a few yards then crawl under a bush or tree and lay down and expire.

Now a bow on the other hand kills by bleeding action. Modern broadheads are designed for sustained, accurate flight, and penetration. Once you score a hit the arrow hangs in the would channel cutting the surrounding tissue as the animal moves. Some arrows have heads designed with barb like wings that help the arrow to stay embedded. My father (and hunting companion) has a self healing archery target out behind his house that, according to the manufacturer, is supposed to simulate the density and penetration of a real deer. I am able to sink a broadhead about 12 inches on average into this target at 75 yards. In my experience I usually have to track my kill a bit farther when bow hunting over a rifle shot, but the difference is measured in yards. In 30 plus years of hunting I have only once dropped a buck in its tracks with a bow (a very lucky heart shot). And I have dropped a total of 2 bucks and 1 bull elk in thier tracks with a rifle. Overall I have probably bagged close to 50 big game animals through the years.

So in summary arrows do have less penetrating power overall, but in thier own way they are just as deadly at close range. I have seen deer jump out of the way of an arrow, so stalking and a silenced weapon can be important.

[BonHed]

Couple o' points:

First off the myth that arrow wounds are in some mystical way different from bullet wounds is, well, a myth.



There is something to be said for the sharpness of the object doing the cutting. A ragged wound caused by a dull blade will clot faster than a clean cut caused by a razor sharp blade.

The platelettes in the blood stream are better able to adhere to the more ragged edges of a wound caused by a dull blade. The sharper the blade, such as a razor or scalple, the longer it takes the platelettes to start congregating and forming the clot. That's why when one cuts ones' self shaving with a razor, it bleeds for a good long time.

I would imagine, however, that this is going to be more of a long term, rather than an immediate effect. Long term being a matter of minutes, rather than seconds.

And the brain certainly does play a role. Blunt trauma causes more shock to the body, which the brain has different methods for handling. Muscles will clamp down around severed blood vessels, and can prevent or lessen the blood flowing from a severed limb (this is, of course, only a very temporary effect; one had better get a tourniquette around that severed limb pretty quick). This happens automatically when the brain registers the shock of the cut. A particularly sharp blade may cut so cleanly as to produce less shock to the body; the brain may not register the wound correctly, and the proper signals may not be sent to the muscles around the wound to force them to clamp down.

Now this is all subjective. Lots of different factors can contribute to this scenario, and it doesn't always happen the same way for everyone, everytime. But there are different kinds of wounds, all of which affect the body in different ways.

[Eosin]

The easy answer is to refer to EMEDICINE.


Gunshot wounds (GSWs) have a much broader injury pattern due to several mechanisms [than Stab Wounds [SW]]. First, any structure directly in the path of the missile suffers a loss of integrity. Approximately 85% of abdominal wall GSWs penetrate the abdominal cavity, and 95% require a surgical procedure for correction. Injury also is caused by fragmentation of the bullet on impact.

The transfer of kinetic energy from the missile to surrounding tissue as it traverses its path creates injury in several unique fashions. Kinetic energy is directly proportional to the mass and the square of the missile velocity; impact velocity directly relates to the wounding potential of a projectile. Missiles are categorized by their velocity profile into low-, medium-, and high-velocity projectiles. The impact speed is affected by several factors, including target distance, missile velocity, missile mass, missile shape, and drag. A missile creates longitudinal and horizontal shock and shear waves as it traverses different media. These, in turn, lead to cavitation of surrounding structures. The temporary cavity formed can contuse and lacerate tissues, fracture vascular intima, and rupture large vascular conduits. Dependent upon the energy imparted by the missile, these injuries may extend a significant distance from the bullet track.

Your brain has little to do with clotting processes except in cases where you engage the flight or fight syndrome and begin dumping tremendous amounts of endogenous pressors into your blood stream. This may keep you alive a bit longer but at the end of the day you are still dead.

In my subjective, but educated, opinion the wounds and treatment for the two mechanisms of injury are basically equally leathal. Penetrating wounds to the abdomen or thorasic cavity are gonna require immediate surgery 80% of the time or death will rapdily follow the wound.... If not from profound shock, then from secondary infection (the colon is full of doodoo and the lungs aren't meant to be deflated. Your other options include the liver, heart, great vessels, or the ever so awesome ~ "dude, you got lucky. You should be dead.")

Gotta go to bed.

[Markdoc]

There is something to be said for the sharpness of the object doing the cutting. A ragged wound caused by a dull blade will clot faster than a clean cut caused by a razor sharp blade.

Sounds reasonable - but is not actually true, and we have 150 years of surgical experience to confirm this. The reason we use the sharpest possible blades (or lasers) in surgery is not to leave a clean edge, but to reduce the amount of collateral damage.


The platelettes in the blood stream are better able to adhere to the more ragged edges of a wound caused by a dull blade. The sharper the blade, such as a razor or scalple, the longer it takes the platelettes to start congregating and forming the clot. That's why when one cuts ones' self shaving with a razor, it bleeds for a good long time.

Again, sounds reasonable, but is untrue. Platelets adhere to the surface of cells via integrins. All that is necessary is an intact cell membrane expressing integrins (and yes, other receptors) and the "roughness" of the surface is, quite literally irrelevant. Platelets are very very flexible and will flow over surfaces ike mercury - but without integrin expression, they won't stick. And integrin expression is regulated at the level of individual cells and tissues, not systemically (good thing too, or we'd all be dead of internal blood clots).

If you've ever done microsurgery (and I have), you'll know that the finest blades humanity can produce leave a mess at the cellular level somewhat akin to cutting watermelons with a chainsaw. It's why we use lasers today, which can cut at a cellular level, where we can.

The reason your face bleeds a lot when you slice it with a razor, is because it's full of blood vessels, just under the surface (it's why it goes red when you overheat, whereas your stomach does not - at least to the same degree). Scrape it with asphalt (and I've done that too, back in my skateboarding days) and it will bleed every bit as freely, I promise you. The difference - and the reason we are surprised at how much blood there is after a shaving accident - is because you don't notice the cut as much as you do road rash.


And the brain certainly does play a role. Blunt trauma causes more shock to the body, which the brain has different methods for handling. Muscles will clamp down around severed blood vessels, and can prevent or lessen the blood flowing from a severed limb (this is, of course, only a very temporary effect; one had better get a tourniquette around that severed limb pretty quick). This happens automatically when the brain registers the shock of the cut. A particularly sharp blade may cut so cleanly as to produce less shock to the body; the brain may not register the wound correctly, and the proper signals may not be sent to the muscles around the wound to force them to clamp down.

Nope again. Muscle spasm and closing of the capilliary bed is triggered primarily via local systems (it is, in fact, initiated at a sub-cellular level, characterized by hypermetabolism, accelerated gluconeogenesis, increased fat oxidation, and negative nitrogen balance, all occurring within seconds after injury). You can, in fact, induce the exact same responses (with identical kinetics) in acephalic individuals (ie: which have no brains) or in deeply sedated humans, where there is almost no brain activity, or indeed, in muscle tissue where the nerves are totally destroyed, so that there is no feedback to the CNS at all (this happens in leprosy patients, where I am most familiar with it from clinical experience).

We are, of course, talking about the acute response to injury (what's sometimes called the "Ebb Phase": the brain does play a role in coordinating overall responses to trauma (thee "Flow Phase") - but this is well after the initial phase - it can last as long as a month. Shock is induced by the body's response to injury (or percieved injury: you can induce shock without any actual trauma) - it is not an essential part of the response or the cause of it, as indicated by the fact that an excited individual can respond normally (at the cellular and tissue level) to injury without suffering any shock.


Lots of different factors can contribute to this scenario, and it doesn't always happen the same way for everyone, everytime. But there are different kinds of wounds, all of which affect the body in different ways.

Now, THIS on the other hand is true. Other factors circulating in the body can greatly modify the effect of trauma. What matters is the degree of trauma, the location of the trauma and external factors such as adrenaline levels. What *doesn't* matter is whether it's slicing, crushing or piercing. A bullet in the butt and an arrow in the butt will induce a similar response, all things being equal, as will an arrow in the gut and a bullet in the gut.

cheers, Mark

[BonHed]

Again, sounds reasonable, but is untrue. Platelets adhere to the surface of cells via integrins. All that is necessary is an intact cell membrane expressing integrins (and yes, other receptors) and the "roughness" of the surface is, quite literally irrelevant. Platelets are very very flexible and will flow over surfaces ike mercury - but without integrin expression, they won't stick. And integrin expression is regulated at the level of individual cells and tissues, not systemically (good thing too, or we'd all be dead of internal blood clots).

Here's hat I learned when I studied human anatomy in college: platelets are sticky and adhere to the edges of objects they find inside a blood vessel (such as a cut, or a device implanted to strengthen a blood vessel wall). Once they have begun to stick to the surface, they then release chemicals that attract more platelets. They form fibrin chains that trap yet more platelets, eventually forming a clot.

http://www.besthealth.com/besthealth/bodyguide/reftext/html/cardio_sys_fin.html

http://en.wikipedia.org/wiki/Platelet (it's Wikipedia, so it must be taken with a grain of salt - no telling how accurate it is, but it does follow along with information found elsewhere)

So the smoother the cut, the longer it will take for the clot to form. A scalpel blade is going to leave a much smoother cut than one from a less sharp blade. Since a blood vessel is fairly elastic and small, let's use an analogy of something that we can wrap our heads around: plastic wrap. Cut it on the sharp metal edge provided on the box, and you get a smooth, clean cut. Tear it with your fingers and it deforms, ripping away in ragged chunks. Now try to fit the two sets of edges back together. Which set fits together with the least amount of gap? The one cut smoothly on the edge of the box.

Now sure, on the cellular level, both cuts are ragged, since neither breaks the bond holding the cells together. But there is more surface area exposed on the stretched, deformed edge. So in a blood vessel, this would mean more exposed collegen, so more platelets adhere.


The reason your face bleeds a lot when you slice it with a razor, is because it's full of blood vessels, just under the surface (it's why it goes red when you overheat, whereas your stomach does not - at least to the same degree). Scrape it with asphalt (and I've done that too, back in my skateboarding days) and it will bleed every bit as freely, I promise you. The difference - and the reason we are surprised at how much blood there is after a shaving accident - is because you don't notice the cut as much as you do road rash.

Yes, faces do bleed a lot; perhaps that wasn't the best example. So how about fingers? I've managed to cut my fingers on both well used pocket knives (still somewhat sharp but not honed) and scalpel blades fresh out of the package. Boy, did that scalpel cut bleed a lot longer than the pocket knife cut. Same amount of pressure applied, comperable wound sizes. The scalpel blade cut left almost no scar, while the pocket knife cut left quite the nasty one. I will say this, however: the scalpel cut healed a lot faster, and it didn't hurt nearly as much as the cut from the much duller pocket knife. Not as much collateral tissue damage to repair.

Now, how much of an effect does this have immediately in a combat situation? I dunno, I've never been shot a bullet or an arrow. Do people/animals die immediately from both? Yes. Is it possible to bleed to death from both? Yes.

In the end, what usually kills a person/animal is lack of oxygen to the brain; whether this is caused by a bullet or an arrow is moot. But I do believe that there is a difference in the effect of a wound caused by different objects, be they crushing, slicing, puncturing, be they caused by a wickedly sharp knife or a dull metal edge.

[Remjin]

Wow... real science!

Always good to have a surgeon on board, thanks for the incites. Now I'm going to happily go back to keeping my combats simple and uncomplicated with cinematics in mind, because all these facts are going to confuse me. :eek: Plus, they'd be really boring to use in play.

However, I do feel better informed, so thank you. :D

[Dog Soldier]

The reason for an arrow to be as sharp as possible is so that it'll penetrate as deeply as possible. The deeper the wound the more it'll bleed. Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.

[Remjin]

...what about an arrow with a brass fist on the end? =)

[Markdoc]

Here's hat I learned when I studied human anatomy in college: platelets are sticky and adhere to the edges of objects they find inside a blood vessel (such as a cut, or a device implanted to strengthen a blood vessel wall). Once they have begun to stick to the surface, they then release chemicals that attract more platelets. They form fibrin chains that trap yet more platelets, eventually forming a clot.

Mostly true - apart from the "sticks to edges" bit. Cells don't *have* edges. Platelets *aren't* "sticky" (otherwise your blood would clot inside your vasculature) And platelets don't stick to collagen (If they did, they'd stick as soon as they entered your heart, which has plenty of exposed colagen) As stated before, platelets adhere via receptors (primarily integrins). It's a very specific process. Now integrins are not normally expressed on the inner wall of cells lining the blood vessel - but when the vessel is ruptured the platelets suddenly gain access to cells that *do* express it. "Roughness" has nothing to do with it: we're not talking about velcro here - it's a cell surface phenomenon and what defines how fast a clot forms is:
1: blood flow into the damaged area. More platelets, faster clotting.
2: the size of the hole. Rough or smooth, doesn't matter. When it comes to trauma, size counts. A big hole will not seal readily, simply because it takes time to fill it all with fibrinogen. And of course, if you have a big hole, time is usually something you don't have much of.


Cut it on the sharp metal edge provided on the box, and you get a smooth, clean cut. Tear it with your fingers and it deforms, ripping away in ragged chunks. Now try to fit the two sets of edges back together. Which set fits together with the least amount of gap? The one cut smoothly on the edge of the box.

Now you're changing gears. A big hole will take longer to plug - but then, I said that in my first post. "Roughness" doesn't matter. Size does. To take your plastic wrap analogy, instead of using your fingers, poke a hole in in with a sharp pencil. Now you have a "bullet hole" - which dispite having slightly raggy edges will actually fit together and seal nicely.



I've managed to cut my fingers on both well used pocket knives (still somewhat sharp but not honed) and scalpel blades fresh out of the package. Boy, did that scalpel cut bleed a lot longer than the pocket knife cut. Same amount of pressure applied, comperable wound sizes. The scalpel blade cut left almost no scar, while the pocket knife cut left quite the nasty one. I will say this, however: the scalpel cut healed a lot faster, and it didn't hurt nearly as much as the cut from the much duller pocket knife. Not as much collateral tissue damage to repair.

I've also cut myself with scalpel blades more times than I can count (never at work though - always when modelling). Scalpel cuts do bleed like billy-o, but then they are almost always deeper than cuts with blunter blades. When I have given myself a good cut with a knife (the bleeding'est cut I think I've ever had, I gave myself with a vegetable knife while cutting up yams for a thanksgiving dinner) they bleed as long and as freely. But yes - scalpel wounds - any slicing wound actually - will heal more cleanly than a ragged wound, simply because it's easier to fit the ends together: hence my earlier "collateral damage" comment.



Now, how much of an effect does this have immediately in a combat situation? I dunno, I've never been shot a bullet or an arrow.

But I have. And I have never bled so much as I did from one small bullet wound. I've seen other people shot too. Trust me, if you haven't seen someone shot through the chest, you haven't seen bleeding. I must admit I have never seen anyone shot with an arrow, though :D


In the end, what usually kills a person/animal is lack of oxygen to the brain; whether this is caused by a bullet or an arrow is moot. But I do believe that there is a difference in the effect of a wound caused by different objects, be they crushing, slicing, puncturing, be they caused by a wickedly sharp knife or a dull metal edge.

In the long term, yes. In the short term, no. In the short term, what counts is how big the wound is and (most of all) where it is. That's not my own opinion but that of trauma surgeons who have looked at (and treated) thousands of wounds caused by knives, bullets, broken glass and similar tools. I've got more experience and knowledge than most folks (I'm a doctor, a researcher and as of last month, full professor at a medical school) but I'm no surgeon and not a trauma specialist. In this case, I accept the judgement of those who are.

cheers, Mark

[Markdoc]

The reason for an arrow to be as sharp as possible is so that it'll penetrate as deeply as possible. The deeper the wound the more it'll bleed. Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.

You got it! And the reason for a broadhead is that a wide deep wound bleeds more than a narrow deep wound.

cheers, Mark

[Dog Soldier]

You got it! And the reason for a broadhead is that a wide deep wound bleeds more than a narrow deep wound.

cheers, Mark


:) Thanks! Now I have to wonder why my spellchecker let "th" slide for "the" but changed "imagine" to "image" twice :nonp:

[bigdamnhero]

Image an arrow with a flat disk on the end of the shaft exactly the same weight as a broadhead. Of course it's not going to have th aerodynamics so image both are fired at a range that just clears the bow. The broadhead penetrates flesh and bone deeper.
Believe it or not I have a good friend who, when younger, used to duct-tape pennies over the ends of arrow shafts and he & a buddy would shoot them at each other with compound bows. (I never said he was smart.) Got some nasty bruises, but that's about it.


...and as of last month, full professor at a medical school
Congrats! :celebrate Also thanks [and rep] for the excellent discussion.

[BonHed]

Platelets *aren't* "sticky" (otherwise your blood would clot inside your vasculature) And platelets don't stick to collagen

"Platelets clump by binding to collagen that becomes exposed following rupture of the endothelial lining of vessels. Upon activation, platelets release adenosine-5'-diphosphate, ADP and TXA2 (which activate additional platelets), serotonin, phospholipids, lipoproteins, and other proteins important for the coagulation cascade. " (Source, http://web.indstate.edu/thcme/mwking/blood-coagulation.html)

"...at sites of vascular injury, endothelial cells are damaged or removed. This exposes collagen fibrils, to which platelets adhere with help from von Willebrand factor, a blood protein synthesized by endothelial cells." (Source: http://64.233.167.104/search?q=cache:dHOmZhr86RQJ:www.pik-potsdam.de/~stefan/Publications/Nature/paillardn%26v.pdf+collagen+platelet+activator&hl=en&gl=us&ct=clnk&cd=10)

"Collagen and the GpVI-specific platelet activator collagen-related peptide (CRP-XL) stimulated NO synthesis, as evidenced by increased [(3)H]L-citrulline production, and cyclic GMP (cGMP) formation. After platelet activation by collagen and CRP-XL was normalised,..." (Source: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=16113831&dopt=Abstract)

God, I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").

Perhaps "sticky" was not the best word to describe platelets, but I couldn't think of a better way to describe something that adheres to the surface of another thing. Plus, I saw it used in reference to platelets, so I figured it was safe.


I've got more experience and knowledge than most folks (I'm a doctor, a researcher and as of last month, full professor at a medical school)

Against my better judgement, I feel I must comment on this last statement. There is a major misconception among some learned individuals that what they say must be true, and that statements made by those with "lesser" knowledge cannot possibly be true.

I had a biology professor who swore up and down that the Punett Square was invented by a Frenchman, and that it was pronounced "Pun-ay". He adamantly refused to admit that he was wrong, even when it was pointed out to him, from the text from which he was teaching, that it was invented by an Englishman, Reginald Punett.

I had a physiology professor claim that the Rx symbol came from the Eye of Horus, whom he claimed was the Egyptian god of medicine. He drew the "Eye" on a chalkboard; it resembled the Rx symbol (it may have been something to represnt Thoth, whom the Egyptians recognized as the creator of all sciences, including medicine), but was definitly not the Eye of Horus. After class, I drew for him the correct Eye of Horus, and explained a little about Egyptian mythology. He of course did not believe a word of it. I did not at that time have any sources to document this, but was confident that I knew something of what I spoke.

So in these cases, I, a humble student, was correct, while the professors, with advanced degrees, were wrong. And further, neither of these two professors was willing to admit that they had made a mistake.

Congratulations on your professorship, I do understand that it is a very prestigious honour that requires tremendous study, knowledge, and experience. My father is a professor of Biochemistry, and it is from him that I learned to defend statements that I make where I believe that my knowledge is accurate, and gained the awful habit of not being able to let things go. I curse him daily for it.

And I promise that this is absolutely the final post I will make on the subject of platelets and blood clotting. The horse is dead, let's burry it.

[Eosin]

God, I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").

Perhaps "sticky" was not the best word to describe platelets, but I couldn't think of a better way to describe something that adheres to the surface of another thing. Plus, I saw it used in reference to platelets, so I figured it was safe.

The most interesting part to me was that they back up everything Markdoc said. We tend to use rough terms to describe things in concepts that most people will understand, hence words like "thinning blood" and "sticky platelets." It works well until someone tries to dig too deep into what that really means or uses them in extensions of what would seem to be logicial conclusions.

[BonHed]

The most interesting part to me was that they back up everything Markdoc said.

They do not back up the point with which I had contention, and that was his statement that I quoted.

Technically, I didn't break my promise.

[Remjin]

My head hurts and my nose is bleeding... and I don't have any arrows, scalpels, or knives near me. And it won't stop.

Thanks, guys. =) I think I hurt my brain... erp... me no think so good now.

[Markdoc]

God, I love the internet. I'm sure I can come up with some more sources, but I think three is an acceptable number for corroboration (Google came up with about 342,000 entries for "collagen platelet activator").

Yep, and if you carefully parse those references, you will find that platelets bind poorly - if at all - to collagen itself, but instead bind to an integrin ligand (formerly and still often called von Willebrand factor, now known to be a famiy of related genes referred to as platelet membrane glycoprotein ligands, or PMGLs). To be fair, a decade or two ago, it *was* believed that platelets bound directly to collagen - that's why you find that statement in your first reference, which is from 1989: the age of the dinosaurs in terms of cell biology.

But as we now know, and as I noted previously, this process actually proceeds via very specific ligands and these ligands are expressed on a variety of tissues - including some (but not all) some forms of collagen and on other cells. Control of these ligands is very tissue specific and very tightly regulated and they can be rapidly upregulated in response to a variety of cellular release signals. Think of the collagen as providing a basic skeleton, onto which (as it is laid down) cells place "this goes here" and "press this button in case of emergency" labels. Platelet-activating ligands are not expressed inside the vasculature*, even though there is plenty of exposed collagen there. This is perhaps a more esoteric point than we need discuss here, but it serves as notice that finding articles on the internet is *extremely* useful (I couldn't work without it, these days) - but some caution is needed in interpreting them. This is something I have to hammer into graduate students, who all too often regurgitate chunks of text they don't fully understand (that's not intended to apply to you, btw: it's a general complaint).

There's a general, relatively non-technical overview of the process on Mike Berndt's group website at http://www.cvr.net.au/research/vascularbio.htm - he's considered a leading expert on this question.

In hindsight, I suppose, for general use, "binds to collagen" and "binds to ligands often found on some types of collagen (and some cells)" is close enough. It's not like we're in class: it's just that on technical topics like this, my get-it-exactly-right response kicks in: result of too much association with scientists, I suppose :D


Against my better judgement, I feel I must comment on this last statement. There is a major misconception among some learned individuals that what they say must be true, and that statements made by those with "lesser" knowledge cannot possibly be true.

That's fair enough - I'm usually a little cautious about bring my qualifications forward, and did so only to show I have some idea of what I am discussing. But note that I have never said "I say this, therefore it must be true" - no real scientist would ever use that argument. Personally I delight in puncturing people who take such pompous approach, so I could hardly object to your comment.


And I promise that this is absolutely the final post I will make on the subject of platelets and blood clotting. The horse is dead, let's burry it.

Fair enough - it doesn't have much to do the original discussion, but then that's the boards for you!

cheers, Mark

*Actually in some cases this does happen - some rare forms of Aortic Stenosis, for example.

[bigdamnhero]

Hey, no need to apologize, either of you. I for one have really enjoyed the discussion. :thumbup:
(The parts I could follow anyway. My head starts hurting after awhile and I have to go lie down.)

[Remjin]

... and bravo to both of you for keeping it civil and not taking things personally. Despite my jokes, I did find it enlightening, if a bit technical for my tastes in gaming. =)