An uneven hail of bullets

Gunshot wounds to the head are a major cause of death among soldiers in combat but little is known about where bullets are more likely to impact. A study just published in the Journal of Trauma looked at common bullet entry points among soldiers who died in combat and found clear patterns – but the researchers are not sure why.

The study, led by physician Yuval Ran, looked at Israeli combat deaths from 2000 to 2004 and tracked where bullet entries appeared on the skull (illustrated above), finding that the lower back (occipital region) and front of the temple areas (anterior-temporal regions) were most likely.

The results of our study show that in a combat setting, the occipital and anterior-temporal regions are most frequently hit, as opposed to the anterior-parietal and the posterior-temporal regions, which are rarely hit. Moreover, most of the parietal injuries were in proximity to the occipital bone. In an attempt to explain these findings, we presented them to sniper instructors, only to learn that snipers always aim to center mass, and aiming at high distances to different skull areas is not probable. At this time, we have no plausible theory to explain these findings.

Your first thought may be that the distribution is because helmets better protect certain parts of the head, but as the researchers note, helmets have been shown to be almost entirely ineffective in protecting against direct gunfire.

Getting shot in the head is not just an unfortunate event, it is the result of the interaction between the shooter and the target, and each of their behaviours could affect where bullets are more likely to land.

The researchers also note that the results are strikingly similar to the only other study looking at the location of fatal gunshot wounds to the head, despite the fact that this earlier study only included civilian shootings.

While there is no current theory as to why fatal gunshot wounds are more likely to be distributed as they are, the article suggests that this could be used to save lives in combat.

Effective helmets are not worn by soldiers because sufficient armouring would make them too heavy, but simply adding protective armour to the most common areas would make for a lighter helmet that could stop the majority of fatal bullet wounds.
 

Link to PubMed entry for study.

22 Comments

  1. Stoicbuddha
    Posted September 15, 2010 at 7:24 pm | Permalink

    “Getting shot in the head is not just an unfortunate event…”

    I’m entering this into the Understatement of the Year Award. :)

  2. Posted September 15, 2010 at 7:39 pm | Permalink

    Common sense explains some of this. Since this study seems to include only “kill” shots, including non-lethal head injuries would create a map of lethal injury zones. The jaw line, nose area, and “edges” where helmet deflection become a factor are less likely to be in the lethal zone.

    The concentration to the rear is most likely the result of it being much easier to hit a kill zone when shooting a target from behind than facing a target who may be returning fire.

    • Albatross
      Posted September 20, 2010 at 11:28 pm | Permalink

      “The jaw line, nose area, and “edges” where helmet deflection become a factor are less likely to be in the lethal zone.”

      This doesn’t seem to jive with:

      “helmets have been shown to be almost entirely ineffective in protecting against direct gunfire”

    • J S
      Posted September 29, 2010 at 12:03 pm | Permalink

      Amazing that the article didn’t identify the obvious theories, but to summarise:

      1) For fatal hits, the bullets will be clustered where they are most likely to cause death (i.e. where they will penetrate critical parts of the brain)

      2) Shots to the back of the head will likely be common fatalities, because they likely represent the target being unaware of the attacker, who would be free to aim without the risks of return fire

      3) Peering out from partial cover (behind a rifle or other structure) would mean that the top of the head above the eyes would be exposed more than anything below the eyes

      4) Some of these kills may also be at relatively short-range, and thus the grouping around the temple may be caused by the attacker targeting the area below the helmet (or it could just be caused by point 1, i.e. the shots that hit the rim of the helmet are less likely to be fatal ones as edges can be highly effective deflectors – http://news.bbc.co.uk/1/hi/sci/tech/7811567.stm – so the ones above and below the rim are more likely to be fatal)

      These three or four factors together seem to explain everything observed (theoretically at least).

      Also, as mentioned by others, the study on helmets actually concludes that helmets should have a 12mm air gap between the helmet and the head, not that helmets are by definition useless… i.e. no reason not to re-enforce the parts of the helmet covering the commonly fatal areas

  3. Jon Mellon
    Posted September 15, 2010 at 10:33 pm | Permalink

    Besides the clustering at the back (which I think Omar explains well) are any of the clusters statistically significant?

    Generally they just seem to follow a general pattern of correlating negatively with how easy it would have been for the victim to see his killer.

  4. Posted September 16, 2010 at 1:11 am | Permalink

    I think Omar has it right about the Occipital concentration. An I have a theory for the anterior temporal concentration.

    The study specifies that snipers “always aim to center mass”; which for a side on headshot would be the temporal area. I hypothesise that when standing outdoors people have a tendency to face away from any wind. Thus, any long range shot is likely to be blown toward the anterior prior to impact. I understand that snipers are trained to take into account wind direction when aiming, but this theory explains situations where the wind is only effecting the target, and influencing their direction of facing.

  5. max
    Posted September 16, 2010 at 1:51 am | Permalink

    I wonder if handedness also influences shooting patterns. 90% of people are right handed, this could cause gunshot wounds to cluster to the left side of the front of the head in cases where the shooter used a handgun.

  6. Posted September 16, 2010 at 7:38 pm | Permalink

    Even hypothesizing about the causes for the “concentrations” is a complete waste of time. The sample is far too small to even begin to address whether there are patterns at all. In any random distribution there is going to be random clusters, and the smaller the sample, the more pronounced the clusters may be (the other end of the law of large numbers) and before billions of dollars are spent designing helmets that protect those areas better (if we can make helmets that better protect one part of the head, why not create helmets that better protect the whole head?) we’re going to need proof that these aren’t random clusters, which is something we are currently lacking with 76 data points.

  7. anon
    Posted September 20, 2010 at 8:19 pm | Permalink

    Completely pointless. You need at least 1000 samples to draw any conclusion.

  8. Posted September 20, 2010 at 8:45 pm | Permalink

    The modern kevlar laminate helmet does protect the wearer from some bullet strikes, especially in the case of glancing hits, strikes by bullets that have already passed through or bounced off other materials, and because pistols and carbines (7.62×39) strike lighter blows than full-power rifle cartridges used by snipers and machineguns (7.62x54R). The areas not as well-covered by this admittedly limited protection appear to be the areas where the study found fatal hits were concentrated.

    Note that Mindhacks seems to have misinterpreted the study cited http://www.ncbi.nlm.nih.gov/pubmed/15345967 which addresses blunt trauma injury caused by backface deformation when the helmet stops a bullet but flexing helmet materials still strike a dangerous blow to the skull and brain of the wearer.

    I also wonder if these low skull hits aren’t the result of aiming for the torso of the soldier; a shot aimed at a soldier’s chest that lands only a little high will strike the neck, jaw, or lower part of skull more often than the top of the skull.

    And the head of a moving target is notoriously hard to hit in a hurry even when aiming at it deliberately, even at close quarters. The closer to the center of gravity of the target the more likely you are to make the hit; the top of the head is bobbing and weaving more that the part attached to the neck.

    Seems to me the researchers would need to understand how many other hits (not necessarily fatal injuries) occur to the jaw, neck, and unprotected shoulders and upper chest before dismissing the effect of distribution of hits resulting from shots aimed at other parts of the body. PubMed points to a related study http://www.ncbi.nlm.nih.gov/pubmed/15995476 that found injuries to the neck and face were the most common cause of fatal injury to IDF soldiers.

  9. Ari E-B
    Posted September 20, 2010 at 9:05 pm | Permalink

    Since this paper was using Israeli soldiers for it’s sample size, we should remember that Israeli soldiers are largely engaged in urban guerilla style warfare. When engaging in such a fight, the shooter, being heavily outmanned and under resourced will be trying to compensate with stealth. Therefore they will choose to try and shoot soldiers from behind, which explains the concentration in the back. As for the front, I can only assume those are situations where the soldiers are engaged in a firefight and therefore they are acing the enemy that they are firing upon.

    • former soldier
      Posted October 19, 2010 at 11:32 am | Permalink

      Thanks Ari E-B, I came here to say the exact same thing that these eggheads were missing. It’s classical predator-prey interaction that an ecologist would see right away. This is one reason why you have tribesmen in the Sundarbans wear Tiger masks on the back of their head, as Tigers like to sneak up on their prey from behind.

  10. Andi
    Posted September 20, 2010 at 10:59 pm | Permalink

    Keep in mind, that soldiers are,
    when aiming at the oponent, mainly laying behind their weapon, thus beying protected a some piece of metal in front of their face. The statistical distribution (left/right) may be a result from the asymetrical placement of the face behind the weapon while looking through the sights, with one half of the face being covered with the weapon taking the direct hit in first place.
    What concerns the distribution lower and upper part of the scull, a direct hit to the helmet in the upper part is more likely being deflected due to the impact angle of the bullet not being 90 degrees to the line of fire…
    The latest helmets offering level 4 protection (NIJ standard, rifle shots) are having a 4cm circular band in the lower part. Technically, the same level of protection can be achieved for the upper part, but would indeed render the helmet being heavyer than comfortably wearable…

    • Alexander
      Posted September 22, 2010 at 1:20 pm | Permalink

      I agree. Also, from my own time in the infantry as a NCO, my experience tells me that most riflemen will be righthanded and as such will aim and fire their weapon in a right to left angle. This plus the fact that we aim for the medulla oblongata can be a part of the answer.

  11. Albatross
    Posted September 20, 2010 at 11:32 pm | Permalink

    Here’s an hypothesis: most battlefield deaths from direct headshots may be the result of deliberate killing of one soldier by another soldier (fragging) with a shot to the back of the head during battle. In contrast, most deaths during battle would be the result of injuries to other portions of the body. So when soldier is brought in with gunshot wound to the back of the head, an investigation ought to be launched.

  12. Ranulf
    Posted September 21, 2010 at 8:50 am | Permalink

    Just a thought: could helmets actually be the cause of this pattern by deflecting bullets into those areas?

  13. Sparge
    Posted September 21, 2010 at 12:34 pm | Permalink

    Lots of good comments, but everyone seems to missing the obvious. Aren’t fatal wounds going to be clustered in areas where a bullet is more likely to cause death?

  14. MarkH
    Posted September 21, 2010 at 1:18 pm | Permalink

    I read the linked abstract for a paper on limitations of modern military helmets. If that paper justifies the conclusion that “helmets have been shown to be almost entirely ineffective,” then its abstract is very misleading.

    To equate imperfectly or partially effective, with “almost entirely ineffective,” is a gross distortion.

  15. Spela
    Posted September 24, 2010 at 7:49 pm | Permalink

    I think Sparge is right. This is really similar to this study about planes and armor: http://404uxd.com/2007/08/03/thinking-and-leaping

  16. woodchuck
    Posted October 15, 2010 at 12:01 pm | Permalink

    The shot interact with the shooter, as the article points out. People shot in the back, whether of the torso, leg or head, are fleeing the shooter.
    This seems obvious.

  17. Joce
    Posted October 15, 2010 at 6:49 pm | Permalink

    I think it’s probably due to the interaction between shooter and target.

    eg. If you’re walking down a street the shooter will probably either shoot when you’re about forty yards away or just after you go past him. This would give definite patterns.

    Or … if you’re hiding behind rocks you’re more likely to be hit by somebody who’s flanked you and is above you and within a fairly narrow range of angles on average.

    I bet if you analyzed this and grouped the shots into different combat scenarios the mystery would be solved.

  18. Peterloo
    Posted October 26, 2010 at 9:18 am | Permalink

    In a combat environment targets are either stationary or moving.

    Stationary targets will, in most situations, be behind cover. When in cover a targets only way of surveying its environment is to expose the head at least as far as below eye-level. A stationary target looking out from behind cover presents a relatively good aimed-shot opportunity which would result in a hit in the areas show in the results.

    Moving targets present two different sub categories – crossing targets where the travel vector is, to a greater or lesser extent, across the shooters plane of vision; and the head-on ro going-away target where there is very little lateral movement.

    In the first case shooters with modern semi- (or full) automatic weapons will fire a burst while leading the target. Recoil effects will cause the shot pattern to form a diagonal line into which the target will cross. As center of mass ‘CoM’ (i.e. middle torso) is the default aim-point, chances of a side-on head shot are relatively low.

    In the head-on/going-away situation, the target will in all probability be running in a ‘head-down’ attitude with a reduced distance between CoM and the head. The recoil effect of a burst shot will result in a vertical line of shot from CoM upwards. This will result in a higher occurance of front/rear head strikes in the areas shown in the results.

    This seems pretty logical to me.

    I dont think combat helmets have ever been designed to stop direct fire from hi-vel rounds. Their primary goal has always been to protect against flying debris and low-vel fragmentation. To make a helment capable of stopping hi-vel rounds would place an enormous strain on a combatants neck and would probably severly encumber his ability to move his head quickly.


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