Odd Job's Gunshot Thread

[Axion]

WOW oddjob awsome writeup!

[Odd Job]

@ CobrayCommando

From what I have read I would have to agree. Would you say that there are specific types of bullets that are less likely to do this, perhaps even specific calibers (to settle something in another thread and to satisfy my curiosity) and combinations thereof?

There are several problems as I see it:

1) A bullet of a certain design may have less tendency to deflect upon initial contact, but that does not guarantee reduced deflection on bone once it has entered the body. For example, compare a skull vs a femur shot. In very unscientific tests I have found that the Sentry round, for example, has less chance of deflection from a flat angled surface than an FMJ fired at the same angle. The Sentry is an all-copper bullet with a sharp rim and a short blunt central post. But there is no guarantee that it will maintain that presentation throughout the wound path.

2) I don't have enough cases where ammunition other than FMJ or JHP has been used and has been involved in a bone strike, to make a valuable comment. I have one case where a round that is either a Sentry or a similar copper round went through a knee and embedded in the tibial plateau so that it could not be extracted by the orthopaedic surgeon even though he had access to the base of the bullet. Bu I have another case where an FMJ did the same thing, after first breaking through the femur. More testing is required on bones.

3) Calibre: I can't provide a 9mm vs .45 conclusion when it comes to deflection off bones. Again, I don't have enough cases where the calibre has been determined. I have seen both deflect, but my cases do have a slight bias because of the popularity of 9mm in SA. Also, many of the gunshot wounds we see are single perforations and it is difficult to determine what the projectile was. Even in penetrating injuries the bullet may be fragmented to such a degree that it cannot even be determined whether it was an FMJ or a JHP (in cases where not all the fragments can be recovered). Even if you do see a bullet on a radiograph, and the bullet is intact you may not be able to work out what calibre it is unless you employ special imaging techniques from the start. These techniques are not welcomed in the trauma setting because of the delay and the increased radiation dose to achieve the measurements.

4) There are cases where I confirmed calibre because I examined bullets that were surgically retrieved, and I have therefore confirmed that .45s can and do deflect off bones and through bones just like the 9mm, but I would like to see more .45 cases before I comment further.

I have read that solid bullets with a meplat, or flat point, generally tend to stay on target, especially if they have high momentum. The meplat makes them penetrate more because it keeps them stable and far less likely to yaw.

I can't comment on that because I haven't seen enough shootings with those types of ammunition to make a statistical comment. I have seen several cases, however, where semi-wadcutters have remained intact but nonetheless have tumbled. In one case a semi-wadcutter was deflected from a man's shoulder into his head. In another case a semi-wadcutter went through a guy's neck and tumbled base-forwards. That is a common occurence in gunshot wounds: once the stability of the projectile is compromised by passage through the tissues, the heavier base will tumble forward in many cases. This will happen even if the bullet passes through bone. That first spine case is a good example of this. Note how the bullet 'points' to the entrance wound. I will see if I can find those two semi-wadcutter radiographs and post them here.

If theoretically you knew that several shots you fired had already hit your attacker in the lethal red plate, and the attacker did not cease his assault, where would you recommend aiming? I know this is theoretical because in real life you likely wouldn't see your hits, and in this situation what would you recommend doing?

I would shoot higher if there was anything of value being presented, otherwise I would have to shoot whatever else was available (abdomen and pelvis) and try to get out of that situation. It doesn't mean my choice would be right or that I would succeed. It may turn out that further shots COM would be better.

I recently read a dissertation called "Wound ballistic simulation: Assessment of the legitimacy of law enforcement firearms ammunition by means of wound ballistic simulation" by Jorma Jussila. I am no scientist, and I wonder what your thoughts are on the subject of linking tissue devitalization with kinetic energy dispersed per unit of length traveled by the projectile in tissue. If you haven't read it and are interested PM me and I will email you a copy. It is very detailed and in depth.

I'd like to read that, PM sent.

Essentially I was wondering if, in your estimation, the increased mass of devitalized tissue external of the permanent cavity caused by some ideal bullet fired from a service caliber handgun, that still got a minimum of 12 inches of penetration in calibrated gelatin, would hasten incapacitation or death (by means of devitalised tissue external of permanent cavity) over say, a non deforming FMJ fired from the same handgun? In your opinion what is the relative importance of said devitalised tissue compared to the actual hole left by a bullet?

I would pick such a round over another one (all other factors assumed to be equal) purely because any extra damage that can be done must be a bonus. I don't know whether this devitalised tissue would play a significant role in the immediate incapacitation of that individual (I suspect it won't, unless it has a significant exsanguinating effect) but that damage must be an extra hindrance to his recovery at the very least. In the end that is quite a difficult question because we have to know what tissue is being devitalised (liver is much worse than muscle tissue for example) and we have to know what the mechanism of devitalisation is. To be honest with you, in all my research cases the majority of the wounds of any significance can be attributed to the direct passage of the bullet. But I have seen cases where cavitation has caused additional damage (usually in tissues that are not elastic, eg the liver) and also cases where damage has been found remote from the path of the bullet. I suspect that this remote damage in handgun wounds is not a big factor in the immediate incapacitation of the individual.

It may very well turn out that this question can only be answered on a case by case basis.

[Odd Job]

@ JohnKSa and Axion

Thanks!

[10 MickeyMouse]

Clearly there is a great deal of knowledge abound on this thread, so I will take the opportunity to ask a question for which I think most of us would find the answer useful. Though not directly pertaining to CNS shots, how much can we suppose a given round's penetration may be compromised if the bullet first impacts a rib or the sternum? 12" is generally considered adequate, but what happens to that 9mm,.40, .45 caliber round that got 14.5" in ballistic gelatin if a "normal" rib bone had to be defeated first? I know this is not an exact science by any stretch of the imaginiation, but I figured asking a medical professional who has had a good deal of exposure to GSW's is likely the best place to get a credible answer.

I know what happens on game animals with rifle rounds, but that is a whole different animal (no pun intended). If only my CCW could chamber .25-06

[BillCA]

Odd Job -- my hat is off to you for an excellent series of posts.


A little research of my own may augment your theoretical COM discussion.

Take a look at the attached illustrated human anatomy diagram. While we all know the CNS runs down the middle of the body, you can see, generally, we could form a rectangle the width of the neck straight down the body to the pelvis and include the CNS as well as the thoracic aorta and the inferior vena cava.

Focusing shots in the mid-line of the body between the top of the sternum and the bottom of the ribcage gives us potential to hit one of these critical structures and/or large blood filled organs such as the liver and spleen.

From an external frontal view of a clothed person, the critical zone is the width of the neck down to the belt buckle with higher shots more likely to incapacitate. In a side view I'd be aiming about 3-4" below the armpit in line with the neck to transect lung(s) and heart.

In friendly discussions with a Nevada coroner, he has indicated his experience shows that shots high on the sternum (upper 4") tend to be least survivable. Shots that penetrate the sternum often also penetrate the upper vessels to the heart and/or disrupt the bronchial branches to the lungs. A perforation straight through can hit the upper thoracic vertebrae (T1-4). But as you point out, this is not a sure thing.

[Odd Job]

@ BillCA

I would go with that, yes. Thanks!

@ 10 M M

I have several cases where ribs have been involved and there have been deflections. It isn't something I have studied intently, but I can probably make some observations if I go through my cases and find trajectory information of note in those instances. It will take me a while to prepare that. I am doing a presentation at a conference on Saturday and I have found that the slides need to be converted.
I will get on to this next week (along with CobrayCommando's wad-cutter radiographs). In the meantime my stance on ribs is that they surely play a role in deflection and fragmentation of projectiles. I don't know if I can quantify it, but I'll have a look.

[CobrayCommando]

A thousand thanks for your patience with my questions Odd Job! Your replies were very informative.

Hopefully someone who thinks that all bullets act like phasers will see this thread and realise that bullets tumble, deflect, yaw, fragment etc, and sometimes (perhaps often) require more then one to incapacitate.

I've read the Strasbourg tests paper and the purported recollections of a US military officer that performed animal testing with bullets in the mid 1990s, and while these reports are unconfirmed they both suggested that a bullet hitting the ribs is very likely to deflect because of the slick fatty layer on top of the ribs and curvature of the bone.

[JohnKSa]

...a bullet hitting the ribs is very likely to deflect because of the slick fatty layer on top of the ribs and curvature of the bone.

I'll blab a bit and then let Odd Job correct me.

From what I can gather, if the round is sufficiently energetic, even a deflection has some potential to do significant damage through "spalling". That is bone chips being blown off the back of the bone and becoming secondary projectiles. Again, probably one of those things that is not all that uncommon but that you can't count on as a consistent wounding mechanism.

[BillCA]

Cobray et al,

The ribs also flex quite a bit and that has something to do with the deflection too. One has to keep in mind that it's possible the flexing of the rib -- which means absorbption of energy -- can allow the bullet to deflect, in effect turning forward energy into lateral energy (to the original path -- probably only a few degrees). Additionally, strikes between ribs have been known to take an odd direction after clipping one of the ribs.

The .22 LR is small enough to penetrate the inter-rib spaces with little or no deflection, at least until it hits tissues behind the ribs.

[Para Bellum]

Quote:
I recently read a dissertation called "Wound ballistic simulation: Assessment of the legitimacy of law enforcement firearms ammunition by means of wound ballistic simulation" by Jorma Jussila. I am no scientist, and I wonder what your thoughts are on the subject of linking tissue devitalization with kinetic energy dispersed per unit of length traveled by the projectile in tissue. If you haven't read it and are interested PM me and I will email you a copy. It is very detailed and in depth.

I'd like to read that, PM sent.

Here it is:
http://ethesis.helsinki.fi/julkaisut...a/woundbal.pdf

[Odd Job]

@ CobrayCommando

I have found one of the semi-wadcutter cases for you. The other case probably isn't relevant because although it was a semi-wadcutter it travelled through quite a bit of soft tissue first before striking bone. It ended up base-first at the back of the neck. I've reviewed all the X-rays and CTs of that case and decided it isn't going to be of value here.
Anyway here is an interesting case involving a semi-wadcutter fired by a carjacker:

A middle-aged man was sitting in a parked truck with the engine turned off. A carjacker appeared at the side window and ordered the man out. The man refused to get out and instead started the engine, whereupon the gunman immediately opened fire. Because the vehicle was a truck, the victim was sitting higher than the level of the carjacker's head. So the gunman had to aim up if he wanted to shoot the victim in the head. Fortunately for the victim, the gunman was not accurate and hit him in the right acromion (shoulder) area. Perhaps the error of parallax played a role here, too. The bullet was deflected up from the shoulder into the frontal sinus region of the head; more specifically just lateral to the frontal sinus. The carjacker fled without firing any more shots.

The victim arrived at the hospital fully co-operative and stable. The bullet was palpable under the patient's skin and it was decided to do skull X-rays to determine its exact location. The reason was that if he did not have a fracture and if his frontal sinus was not involved, then he could be kept for observation and avoid having a CT scan of his brain. These are the views that were obtained:





Cars are right-hand drive in South Africa. The victim was facing the gunman at the time of the shooting, looking at him over his right shoulder. This explains how he sustained this unusual wound. On X-ray you can see that all the opacities are of the same density and that there are metallic specks near the bullet. There was no jacketing to be seen.
The films were shown to the neurosurgeon. He was not happy with the position of the bullet, since it could not be proven whether it had breached the sinus or not. A CT scan was ordered. Here is the planning view and three slices (12-14) of the scan of the affected area:









On these slices you can see that the bullet has caused frontal bone fractures (some arrowed in green) and there is now a wound channel from the skin to the frontal sinus. This represents a significant infection risk. The decision was taken to debride the wound and keep the patient for observation and make sure he did not develop an infection. Also you can see that there is air in the tissues (red arrows). This is probably air that entered at the skin breach, but closer to the sinus you cannot rule out the possibility that air from the sinus has come out into the tissues. The parent bullet is arrowed in blue and several daughter fragments arrowed in yellow.
Note that the CT scan gives the false impression that the bullet is hollow. This is an artefact. The bullet was solid lead. No damage to the brain could be seen radiologically (you can't see that on these slices because they have been 'windowed' so that the bone stands out and the soft tissues are suppressed). The patient's shoulder was X-rayed but nothing unusual was discovered. There were no fractures and no metallic deposits. There were no pieces of projectile in his clothing either.
This was a remarkable deflection.

[Odd Job]

@ JohnKSa

From what I can gather, if the round is sufficiently energetic, even a deflection has some potential to do significant damage through "spalling". That is bone chips being blown off the back of the bone and becoming secondary projectiles. Again, probably one of those things that is not all that uncommon but that you can't count on as a consistent wounding mechanism.

I haven't seen any single-surface spalling (but that doesn't mean it can't happen). It is yet another 'thing' I have not investigated. In fact the more questions are asked, the more I realise how much scope remains for all sorts of experiments.
The problem is that most bones aren't solid, so if the far surface has to give up material, it generally has to take a direct knock or it has to give up material because of a fracture that originates on the near side. Bone fracture lines travel faster than bullets and it therefore follows that secondary bone fragments from the near surface are not going to reach the far surface before the near surface fracture line does (assuming that is the direction the fracture is 'propagated'). I'll try to make a nice section here on bone fracture patterns in gunshot wounds. I just have to be careful to find decent material from my files. It may take a while, but I'll get onto it, along with the ribs.

[Odd Job]

@ CobrayCommando and Para Bellum

I have read Jussila's thesis and generally I have to say that while his intent is honourable, he is not in touch with the variables associated with shooting incidents and the medical effects/handling of these. That's my opinion as a radiographer. He wants a magic bullet, that is the bottom line.
Here are a few points:

The impacting bullet must have sufficient energy to reliably do its job and expend its kinetic energy in the target not to create a hazard to bystanders. This will cause an increase in injury to the offender. Unless a bullet does effectively what it is expected to do, the conflict may be prolonged. More shots may be fired and the danger for both bystanders and the law enforcement officials is increased.

and

The residual energy is a significant factor describing the danger to bystanders when the bullet completely penetrates and exits the primary target continuing its flight.

Basically what he wants here is a round that loses all its energy so that it can't exit, or if it does exit it has reduced energy so that it can't hurt anybody else.

The tactical range of a 9x19 mm calibre service pistol is not defined by the external ballistic characteristics of the bullet but the shooter’s ability to accurately hit under stress. A pistol is a difficult weapon to master [Bruchey and Frank 1983] and its tactical range can therefore be considered to be limited to 10 – 15 m.

and

Poor accuracy increases the danger of injury to bystanders and the police official through increased possibility of bullets completely missing the target and thus prolonging the dangerous situation.

Here we will need an LEO's input. I suspect that more shots miss the targets than hit, in actual shootings. Certainly in civilian vs civilian cases that I have seen, there are enough tangential shots alone to indicate to me that misses are common. I can't see this changing. How many years have we had handguns? How many years have we had to train in their use? Yet there are still misses. I put it down to stress and the unique variables involved with each shooting. LEOS are welcome to comment here.

The Swiss delegation to the Expert Meeting of the International Committee of the Red Cross presented a Draft Protocol on Small Calibre Weapon Systems (1994). Recognising that not only bullet expansion but also other factors cause tissue injury, it proposes a limit for the amount of kinetic energy that is released. It suggests prohibiting the use of ‘arms and ammunition with a calibre of less than 12.7 millimetres which from a firing distance of at least 25 meters release more than 20 joules of energy per centimetre during the first 15 centimetres of their trajectory within the human body’.

And how can that figure be reconciled with a terminal trajectory that traverses tissues that are not homogeneous?

Cavitation is caused by pressure setting the tissue into motion. The peak internal pressure [Eisler et al. 1996] does not seem to correlate with the amount of devitalised tissue. This suggests that the devitalisation of soft tissue not in direct contact with the penetrating bullet is caused by the pressure wave induced rapid acceleration and compression that crush the cell structures [Sondén et al 2000].

and

The rule of four C’s is ordinarily used for identifying the devitalised tissue:
- lack of Contractility
- altered Consistency
- altered Colour
- lack of Capillary bleeding

Okay so these are his parameters for determining what devitalised tissue is. Unfortunately his research mixes handgun and rifle projectiles, and the volume of devitalised tissue is determined by a measurement of the debrided tissue, as determined by the subjective impression of the surgeon handling the case. This method lacks precision and throws in confounding variables. As far as I am concerned it sinks the thesis right there.

Although the size of the exit wound is included in the Red Cross wound classification [Coupland 1993 and 2000] and a large exit wound should be considered a warning sign of extensive internal tissue destruction [Janzon 1997] its effects are not totally negative. First of all the existence of an exit wound allows access to the wound channel from both ends and signifies that at least most of the projectile has exited from the wound.

He is placing undue emphasis on the size of the exit wound. In handgun injuries it means nothing. I have 148 cases where I have photographed all the entrance and exit wounds and there is variation in the size of the exit wounds. yes, most are larger, but there are many that are the same size or even smaller. Whether there are fragments left inside or whether the size of the exit wound is larger or smaller than the entrance doesn't mean anything in terms of the severity of the wound.

The rule of four C’s is not unanimously accepted and more conservative approach of excising only the obviously detached tissue has been presented [Fackler 1989, Santucci and Chang 2004]. As stated previously, this view may lead to severe anaerobic infection and possible gas gangrene [Janzon personal communication 2004].

If this was the case (the theory that less aggressive debridement carries the risk of increased necrosis) then we would have ample data for this and hospital procedures would have changed accordingly. I don't see any evidence of this, in fact hospitals are moving towards less invasive treatment of gunshot wounds in general, even abdominal gunshot wounds. Insufficient debridement is a non-issue (and certainly with handgun wounds I can verify this, because most of my gunshot victim cases in Johannesburg could go home the same day, which means no debridement).

Penetration ability of the standard issue projectile must be controlled with minimum and maximum tissue simulant penetration in defined tests with a defined maximum for acceptable residual kinetic energy after penetration of 250mm of simulated tissue.

That's a magic bullet. It does not exist. All that can be guaranteed is minimum penetration in gel.

Using the heavier metals in the front and lighter metals to fill the rear end of the bullet, the centre of gravity can be moved ahead of the point of pressure creating a penetration stable bullet. Combining this construction with expansion would also make the bullet to have the controlled penetration desirable for law enforcement operations. Law enforcement bullet design, especially in rifle calibres, requires more research.

I am not an engineer but it seems to me that the heavy nose and controlled expansion are mutually exclusive. It rules out a hollow point straight away. Perhaps an engineer can comment here.

Then he wants data recorded by physicians attending to gunshot victims so that it can be correlated with data from tissue simulant firings and computer models. These are the data he wants:

Weapon type (if known)
Calibre (if known)
Ammunition type (if known)
Shooting distance (if known)
Impact type (direct/ricochet/through barrier)
Barrier type
Ballistic protection worn
Projectile type (if known)
Projectile retained weight
Projectile degree of deformation
Wound channel length and proximity to vital organs
Entry and exit wound locations
Maximum diameters of entry and exit wounds
Mass of excised tissue
Bone injury classification

In the medical environment, in cases not involving LEOs, it is going to be almost impossible to get these variables: weapon, ammunition, distance, impact type, projectile type, and wound channel length and proximity to vital organs.
These other variables can only be found if the projectile is recovered from the victim during a medical procedure: projectile retained weight and projectile degree of deformation (although the latter may be found if the axis of the retained projectile is such that it can be X-rayed in two planes and an approximate deformation can be assumed, even if the projectile is not going to be removed). The bone injury, entrance and exit locations and clothing and in some cases the barrier can be found. Those are the easiest to get.
Even if you take into account LEO shootings only (where the LEO is the shooter) you still have a problem with projectiles in situ that cannot be retrieved, or even projectiles at the scene that cannot be found or are not complete, when assessing deformation and final weight. Don't forget that you can get projectile fragments deposited in the wound even if it is a perforating injury. This guy hasn't seen a lot of gunshot wounds, and it is obvious by reading his recommendations.

I would say my impression is this: he has a study that links kinetic energy with devitalised tissue. I have issues with how that tissue was measured, but I don't have issues with the concept in principle (that increased kinetic energy leads to more devitalised tissue, when such devitalisation is specified to manifest itself in the manner that he outlines). However, it does not automatically follow that devitalised tissue leads to necrosis. If that was the case then every gunshot victim we sent home without a debridement would eventually end up with gangrene. This leads us to a point where we have to specify an amount of devitalised tissue, and this in turn is confounded by his inclusion of rifle projectiles in the mix.
I am afraid my initial thoughts on this matter are unchanged. I don't think devitalised tissue from the indirect effects of the handgun projectile are very significant in terms of incapacitation. There is variation (according to tissue type) on the prognosis of the gunshot victim.

[Sarge]

...I am afraid my initial thoughts on this matter are unchanged. I don't think devitalised tissue from the indirect effects of the handgun projectile are very significant in terms of incapacitation...

While I'm sure I haven't seen as many shot-up folks as you have, I have seen enough (and real fresh ones) to say that I agree with that last 100%.

PS- Thank you for your excellent contributions on this ever-controversial topic, Oddjob.

[Odd Job]

You're welcome, sir. It is my pleasure to share what I know (as limited as such knowledge is).

[CobrayCommando]

Odd Job, thanks x1000.

Do you have the book "Bullet Penetration, Modeling the Dynamics and the Incapacitation Resulting from Wound Trauma", by Duncan MacPherson? If not you should definately check it out. If you'd like I would be able to scan a couple dozen pages and email them to you.

[Odd Job]

@ CobrayCommando

What a coincidence, my sister has ordered that book for me! She is in Colorado and will mail it to me in London when she gets it.

[JohnKSa]

I haven't seen any single-surface spalling (but that doesn't mean it can't happen).

That would mean that secondary projectiles (bone fragments/splinters) would be FAR more likely to originate from a fracture, as opposed to a deflection.

I hadn't really thought about the fact that bones are "sort of" hollow (at least they're not what we think of as bone through and through), but what you say makes perfect sense.

[CobrayCommando]

@ CobrayCommando

What a coincidence, my sister has ordered that book for me! She is in Colorado and will mail it to me in London when she gets it.

Fantastic, you'll love it.

[Odd Job]

@ JohnKSa

That would mean that secondary projectiles (bone fragments/splinters) would be FAR more likely to originate from a fracture, as opposed to a deflection.

Yes, that fits in with what I have seen so far. Of course if you discuss secondary projectiles that are pieces of bone with an orthopaedic surgeon, he will point out that any loose bone like that can only be as a result of a fracture. What I am saying is, I know what you are getting at in terms of one surface being intact and the other surface giving up bone, but the medics will regard all those loose pieces of bone as fracture fragments regardless of the integrity of the parent bone from which they originated.
I am going to post some fractures caused by gunshots soon.

[Odd Job]

Gents (and any ladies that might be reading too), we have reached the point in this thread where I cannot continue without introducing some medical terminology. It is unavoidable if I am to keep things from becoming bloated and verbose. When dealing with trajectories and anatomy there are certain standard terms we use to describe what part of the anatomy is involved. I don't want to turn this into a medical text, but I need to get the basics out of the way. If you bear with me here then you will appreciate the subsequent bone fracture cases even more.

Firstly, when discussing human surface anatomy, we have a thing called the Anatomical Position. You can think of this as a kind of 'default' position that the person adopts while being surveyed. The anatomical position is as follows:



If you stand up and have your arms straight with your palms facing forwards that is the anatomical position. It is quite important because that is the reference position from which all terminology relating to planes and areas of the body are derived.
The next thing to be aware of, is that all radiographs (X-ray films or images) are viewed as if the patient was standing in front of the viewer in the anatomical position. This means that the patient's left-sided anatomy will be seen on your right and the patient's right-sided anatomy will be seen on your left.
Below I have a representation that illustrates this:



Regardless of whether it is a trauma chart or a radiograph, that is how it is viewed. The patient's left is on your right and vice versa. There are more than 200 bones in the human body, but for the purposes of this thread I will make things as simple as possible. For example I may refer to the patella but I will also put in brackets the layman's term for it (in this case the knee cap).
Okay now this is where things get interesting, because in the hospital you don't want to have to spend a long time describing to a doctor on the phone where this guy has been shot, or where you think this bullet has gone. You don't want to have to write reams of notes just to describe where the injuries are. We need a kind of 'port' and 'starboard' terminology for humans, if you follow what I mean. And that's exactly what we do have. It has to be quite precise otherwise mistakes can be made. Furthermore it has to take into account the fact that a human is not a nice angular geometric shape. You will therefore find that anatomical locations are described with reference either to the body itself, or to a specific limb, or even a specific bone or organ. Here is a simple example, using those legs from before:



If we want to say that the guy got shot in the 'outside surface' of his leg, we use the term lateral. If we want to talk about the 'inside surface' then we use the term medial. All it means is that we divide the limb down the middle and what is outside is lateral and what is inside is medial. This is true whether you are looking at the guy from the front or from behind. Now you can make this quite specific, because you can refer to the medial or lateral aspect of a particular bone if you want to (and I'm going to be doing that quite a lot when I post all those gunshot fractures later). In addition to medial and lateral we also like to specify which end of the bone we are talking about. For example your tibia (or shin bone) starts at the knee joint and goes down to the ankle joint. Generally when talking about limbs, the part that is closer to the body is called proximal and the part that is furthest away is called distal. In the image above I have indicated the lateral aspect (or side) of the left lower limb and I have also indicated the proximal portion (or nearest half) of the right tibia.
But what about front and back? Here is an image of the right leg, viewed from the medial aspect:



Again, the limb is divided down the middle. Everything to the front is called anterior and everything to the back is called posterior. But if we want to be more specific, we can specify a location that is relative to a particular anatomical feature. For example in that image, I have divided the patella (knee cap) into a front and back half (anterior and posterior portion) with a black line. Everything forward of that line (in the direction of the black arrows) is anatomy that we say is anterior to the patella. Everything behind that line is anatomy that is posterior to the patella, even though when we were talking about the whole limb, some of that anatomy was considered to be anterior.

Continued...

[Odd Job]

If we look at a hypothetical gunshot trajectory we can start to describe where the bullet has gone:



In this case the bullet has entered laterally on the left, exited medially on the left and re-entered medially on the right. We could further specify that this trajectory is superior to inferior (from high to low). Or you could say it entered the left thigh distally, exited distal to the level of the entrance wound, and then re-entered the right lower leg distally. And somewhere in the trajectory there was a deflection. The observation would be that the projectile is lodged in the medial aspect of the lower leg, distally. To find out whether it is anterior or posterior would require another X-ray from the side. If you imagine a cross-section of the limb, you can appreciate the various terms used to describe the possible locations of retained projectiles within that limb:



Now you can see that we have terms for a location that is not quite posterior but not quite lateral for example. The proper term for that is postero-lateral. And there you can see the two planes of division that are used to determine whether anatomy is posterior or anterior (coronal plane) or whether the anatomy is medial or lateral (sagittal plane). The actual plane presented on your screen is the axial plane, and that is the 'extra plane' that you see on CTs for example.

Here is another hypothetical trajectory:



In this case, if you look at the surface, you will see that the bullet entered the knee laterally on the left, passed through the distal femur (suffering fragmentation) and then a portion of the original projectile exited medially and superiorly. We don't know where that portion of the projectile is. It didn't hit the other leg, so I have a question mark there. However we do have a retained fragment. We would describe that as having travelled superiorly and centrally (neither lateral nor medial) and we would need further X-rays to determine whether it was within the femur or not. If bone fragments came off the fractured femur, they would more than likely be projected medially, in the direction of projectile travel. But that doesn't mean they would not be able to move anteriorly or posteriorly in relation to the projectile's trajectory.

This may seem complicated to you if you don't have a medical background, but if you at least know what medial is and what lateral is, that is a good start. It can get a lot more complicated, particularly when discussing hands and fingers. The anatomical position dictates that the thumbs are lateral to the little fingers (see the first image again), but you have lateral and medial aspects of each finger to consider, when discussing gunshot wounds of the hand and digits.

You have not been charged for this lesson

[Dr. Courtney]

I have read Jussila's thesis and generally I have to say that while his intent is honourable, he is not in touch with the variables associated with shooting incidents and the medical effects/handling of these. That's my opinion as a radiographer. He wants a magic bullet, that is the bottom line.

I don't get that impression at all from the Jussila thesis. Like all works of this size and complexity, the thesis has strengths and weaknesses. However, it seems odd to make a judgment on the author's motive based on a scientific work. There is no hint of a desire for a "magic bullet" in the outline of objectives on page 48.

Basically what he wants here is a round that loses all its energy so that it can't exit, or if it does exit it has reduced energy so that it can't hurt anybody else.

This is a cultural/political view regarding the use of force by law enforcement. Its presence in the thesis helps justify the work in academic and government circles, but such a view does not impact the scientific validity of the work. It simply acknowledges that there is some demand for law enforcement bullets to work this way in Finland, not a scientific assertion that all bullets should work this way.

And how can that figure be reconciled with a terminal trajectory that traverses tissues that are not homogeneous?

When quoting something as long as a thesis (over 100 pages), it would be nice if you included page numbers. Nearly half the thesis (47 pages) is a review of the ballistics literature, and you end up quibbling with Jussila over statements that are not original to him, but that he is relating from the literature. You might quibble with the original authors about the content of the statements, but you could really only quibble with Jussila about whether the statements accurately reflect the original work.

Okay so these are his parameters for determining what devitalised tissue is. Unfortunately his research mixes handgun and rifle projectiles, and the volume of devitalised tissue is determined by a measurement of the debrided tissue, as determined by the subjective impression of the surgeon handling the case. This method lacks precision and throws in confounding variables. As far as I am concerned it sinks the thesis right there.

Once again, you are attributing to Jussila assertions that he is relating from the literature in the review portion of his thesis (p 41). Jussila's review is balanced and acknowledges that there are alternate views in the literature as well. The "Review of the literature" portion of a thesis can usually only sink a thesis if important viewpoints are omitted, if major mistakes are made in attribution, or if the reviewer ascribes assertions to the original authors that are not present in the works cited.

He is placing undue emphasis on the size of the exit wound. In handgun injuries it means nothing.

Jussila is discussing the Red Cross wound classification system, not making his own assertions here. Once again, you are attributing to Jussila assertions that he is not making.

Quote:

If this was the case (the theory that less aggressive debridement carries the risk of increased necrosis) then we would have ample data for this and hospital procedures would have changed accordingly.

The use of better antibiotics allows for less debridement. In the absence of antibiotic availability, the negative impact of less debridement would be much more obvious.

That's a magic bullet. It does not exist. All that can be guaranteed is minimum penetration in gel.

A maximum penetration in gel can also be guaranteed, as well as a specified energy after penetrating 250mm of gel. Also keep in mind that he is discussing requirements for a "standard issue projectile" for a specific cultural and political situation (Finland). He is not making a global recommendation.

In addition, Wolberg showed that penetration in humans is well correlated to gelatin. There is a wider variation in humans, of course. But one could probably say with some degree of confidence that most bullets are unlileky to penetrate humans more than 150% of their maximum penetration in gelatin.

I am not an engineer but it seems to me that the heavy nose and controlled expansion are mutually exclusive. It rules out a hollow point straight away. Perhaps an engineer can comment here.

What about a design something like the Corbon Pow'r Ball with a tungsten or depleted uranium ball up front?

Then he wants data recorded by physicians attending to gunshot victims so that it can be correlated with data from tissue simulant firings and computer models. These are the data he wants:

Weapon type (if known)
Calibre (if known)
Ammunition type (if known)
Shooting distance (if known)
Impact type (direct/ricochet/through barrier)
Barrier type
Ballistic protection worn
Projectile type (if known)
Projectile retained weight
Projectile degree of deformation
Wound channel length and proximity to vital organs
Entry and exit wound locations
Maximum diameters of entry and exit wounds
Mass of excised tissue
Bone injury classification

In the medical environment, in cases not involving LEOs, it is going to be almost impossible to get these variables: weapon, ammunition, distance, impact type, projectile type, and wound channel length and proximity to vital organs.
. . .

This guy hasn't seen a lot of gunshot wounds, and it is obvious by reading his recommendations.

Actually, the text is clear that Jusilla does not expect all of the desirable information to be available in every case. However, there is nothing worng with the approach of collecting all of the available data and restricting a given analysis technique to the subset for which the needed information is available.

I would say my impression is this: he has a study that links kinetic energy with devitalised tissue. I have issues with how that tissue was measured, but I don't have issues with the concept in principle (that increased kinetic energy leads to more devitalised tissue, when such devitalisation is specified to manifest itself in the manner that he outlines). However, it does not automatically follow that devitalised tissue leads to necrosis. If that was the case then every gunshot victim we sent home without a debridement would eventually end up with gangrene.

Devitilized tissue that is not debrided presents the risk of gangrene and other infections. Better anitobiotics significantly reduce this risk. But what shall we do when the infectious agents become more resistant even to the better antibiotics? With appropriate use of prohpylatic antibiotics, splitting hairs over how much devitalized tissue becomes necrotic is not that important.

However, nor can you assert that the absence of infection is proof that none of the devitilized tissue becomes necrotic.

I am afraid my initial thoughts on this matter are unchanged. I don't think devitalised tissue from the indirect effects of the handgun projectile are very significant in terms of incapacitation. There is variation (according to tissue type) on the prognosis of the gunshot victim.

Jussila is very clear in his distinction between wound ballistics and incapacitation ballistics. His work on devitilization of tissue is relevant to trauma treatment, particularly in cases where effective antibiotics are unavailable. I do not believe that Jussila asserts any importance of his link between energy and devitilized tissuue to the subject of incapacitation.

Michael Courtney

[Odd Job]

When quoting something as long as a thesis (over 100 pages), it would be nice if you included page numbers. Nearly half the thesis (47 pages) is a review of the ballistics literature, and you end up quibbling with Jussila over statements that are not original to him, but that he is relating from the literature. You might quibble with the original authors about the content of the statements, but you could really only quibble with Jussila about whether the statements accurately reflect the original work.

My comment in this thread, on Jussila's thesis, is not an article in a peer-reviewed journal. It was made on the not unreasonable assumption that the gentleman who asked me about it had read the whole thesis. If the lack of page numbers was an inconvenience to you, that is most unfortunate. I will provide them specifically for you this time.
As for quibbling with Jussila, he is not immune from critique when he subscribes to cited material in the review part of his thesis. This is evident here:

The most critical opponent of the “kinetic energy deposit” proportionality to tissue devitalisation is Martin Fackler [Fackler 1987]. The core of Fackler’s reasoning is that too much tissue is excised by the surgeons. This line of thinking does not seem to have gained undivided acceptance and is countered by saying that unless devitalised tissue is removed a severe anaerobic infection will result with heightened probability of perfringens (gas gangrene) jeopardising the life of the patient [Janzon personal communication 2004].

Jussila has his objectives and it is clear when reading the whole thesis that this is the line he is taking. If I am critical of that (and the references he uses to support that), then that is my valid opinion. You are welcome to yours.

Quote:
I have read Jussila's thesis and generally I have to say that while his intent is honourable, he is not in touch with the variables associated with shooting incidents and the medical effects/handling of these. That's my opinion as a radiographer. He wants a magic bullet, that is the bottom line.

I don't get that impression at all from the Jussila thesis. Like all works of this size and complexity, the thesis has strengths and weaknesses. However, it seems odd to make a judgment on the author's motive based on a scientific work. There is no hint of a desire for a "magic bullet" in the outline of objectives on page 48.

Well, we got different impressions then. I didn't arrive at mine from the objectives, I arrived at it from his proposals in Paper 1 on page 60, under the heading "To avoid superfluous injury and unnecessary suffering to the offender" and from the general tone and drift of his paper.

The use of better antibiotics allows for less debridement. In the absence of antibiotic availability, the negative impact of less debridement would be much more obvious.

That's speculation on your part. The jury is out on low velocity gunshot wounds and antibiotics (the question of whether to use antibiotics at all in simple cases). There is adequate support for the use of antibiotics routinely in the treatment of high velocity gunshot wounds.

Here is the most recent article I can find on this subject:

http://www.jaaos.org/cgi/content/full/14/10/S98

Devitilized tissue that is not debrided presents the risk of gangrene and other infections.

How do you arrive at that conclusion?

Actually, the text is clear that Jusilla does not expect all of the desirable information to be available in every case. However, there is nothing worng with the approach of collecting all of the available data and restricting a given analysis technique to the subset for which the needed information is available.

There is nothing wrong with the approach, but I have stated my reasons why the majority of those variables cannot be found. It is a matter of experience, and seeing what happens in real shootings. I recommend both you and Jusilla spend some quality time at a level 1 trauma center and get back to me on how many of those variables you can find when dealing with gunshot victims.

Quote:
I am not an engineer but it seems to me that the heavy nose and controlled expansion are mutually exclusive. It rules out a hollow point straight away. Perhaps an engineer can comment here.

What about a design something like the Corbon Pow'r Ball with a tungsten or depleted uranium ball up front?

I can see the headlines now: "Outrage as Finnish police shoot man with depleted uranium."
Setting aside the legal and ethical issues, I doubt that a small tungsten sphere or DU sphere would be enough to shift the center of gravity of any police projectile to the nose. My guess is that the amount of DU or tungsten needed to shift the center of gravity forward is not compatible with an expanding projectile.
Once again, we need an engineer's comment on that one.

[Dr. Courtney]

Well, we got different impressions then. I didn't arrive at mine from the objectives, I arrived at it from his proposals in Paper 1 on page 60, under the heading "To avoid superfluous injury and unnecessary suffering to the offender" and from the general tone and drift of his paper.

This goal comes from the political realities of the author's country. Goals that arise from political and cultural considerations should not be considered to detract from the scientific validity of a work.

I have personally seen hundreds of gunshot wounds and I am well aware of a wide range of variables make analysis challenging.

I can see the headlines now: "Outrage as Finnish police shoot man with depleted uranium."
Setting aside the legal and ethical issues, I doubt that a small tungsten sphere or DU sphere would be enough to shift the center of gravity of any police projectile to the nose. My guess is that the amount of DU or tungsten needed to shift the center of gravity forward is not compatible with an expanding projectile.
Once again, we need an engineer's comment on that one.

You don't need to shift the center of gravity "to the nose" merely slightly further forward. A DU or tungsten sphere can shift the center of gravity sufficiently forward to significantly improve stability during penetration. This is an engineer's comment on the matter.

Michael Courtney, PhD