Several years ago, I ran a series of posts on my Laws of Trauma. I assembled them into  newsletter that contained all nine that existed at the time. If you’d like to download it, just click this link.

I’ve  been struck by another pattern, and I think it’s about time to add the tenth law. Weirdly enough, it was inspired by Dancing With The Stars. You’ll see what I mean.

Here is the Tenth Law of Trauma:

“In trauma, it generally takes two to tango”

So what does this mean? When dealing with injury, there are a few broad quantitative categories.

• Single person mechanism. This is one extreme. Common examples would be the elderly fall, a single vehicle car crash, or a self-inflicted stab or gunshot. There is a single “point of failure” that only the individual involved can manage, but for various reasons they do not or cannot. This law does not apply.
• Multiple person mechanism. This is the other extreme, and thankfully is not seen very often at all. Examples are a tour bus crash, house explosion, or mass casualty event. Once again, those involved usually have little ability to recognize or avoid the imminent event, and the tenth law is null and void.
• Two person mechanism. This one is very common, and is exemplified by the two car crash, pedestrian struck, or the various flavors of assault. And this is the one that the tenth law applies to.

When two people are involved in an event that leads to traumatic injury, there is usually (but certainly not always) a set of checks and balances that is present. And frequently there is at least one opportunity to avoid the event.

In the case of a two vehicle crash, one driver may have “gone off the reservation” and ignored the usual traffic laws for whatever reason. But the second driver usually has an opportunity to recognize this and change their behavior in order to avoid the situation. However, if they are distracted, impaired, or making assumptions about how other driver behave they can still get into trouble. Thus, it takes two.

What about the pedestrian struck? Likewise, the driver or the pedestrian may have done something nonstandard. Wear dark clothes at night. Glance at their phone while driving. Look at their passenger a bit too long while having a conversation. Once again, the other participant may have an opportunity to see the result of this unexpected behavior and jump or swerve out of the way.

Interpersonal violence it a bit more tricky. Sure, one of the potential participants may get wind that something is up and try to avoid or defuse the situation. But not always. And this situation is heavily charged with emotion and social pressures and is much more difficult to change or avoid.

Bottom line: Many, but certainly not all,  “two-person” mechanisms of injury are avoidable if both of the individuals involved are mentally present and attentive to their surroundings. Look at your own patient population and see how often this applies. You may be surprised!