This example starts by saying that the most commonly cited cause of medical error during surgery is anatomical variation. All right. I just want to pause there for a second. The most commonly cited cause of medical error is that people are different. That kind of blows my mind a little bit, but let's keep reading.
There are 10 named variants in the arrangement of blood vessels that lead to the kidney and the gallbladder. The three most common are shown in the image to the right. The locations of the right hepatic artery (RHA) and left hepatic artery (LHA) are labeled in each image. Alright. Before we look at the image, let's just see what it's going to ask us.
It says using information from the image, why do you think textbooks usually only present 1 blood vessel branching structure? That's a. And b, it says why you think that may sometimes be a problem? Alright. So with that in mind, let's look at the image.
Alright. We have a big blood vessel running up and down, and then we have sort of complex branching blood vessels coming off of it. We don't really need to worry about all the details of it, but we see the RHA and the LHA. And in the first one, they're sort of branching off at the top. And it says that that variant is about 55 to 60 percent of the population.
Now type 2 looks almost just the same as that, but you can see here the LHA is now branching off from a completely different place than where it did in type 1, and that different branching pattern represents about 10% of the population. Now let's look at type 3, also representing about 10% of the variation. Well, now the LHA is back where it was originally, but the RHA, the right hepatic artery, now branches off from a completely different spot than it did before. Now it's branching off a completely different blood vessel down at the bottom. Okay.
So why do you think we only learn 1? Well, those three variants right there only comprise something like 75 to 80% of the population. There are 10 named variants. I'm just going to say too much variation to know it all, at least in an introductory anatomy and physiology class. Right?
If you're a liver specialist, yeah, you probably know all 10 variants pretty well. Okay. Now why do you think that might be a problem? Well, imagine you're an ER doctor, an ER nurse, and you're thrown into this emergency surgery with stabbing or something near the liver. Do you think that you know all 10 named variants?
Will you be able to recognize the difference and understand exactly what blood vessels you're looking at? It would be really difficult to, right, for the exact same reason. If you're not a specialist on the blood vessels of the liver, there is probably too much variation to know at all. And that can be a problem if that variation is really critical to know. Okay.
With that, just remember, we're learning reference bodies. We're learning the most common. That does not mean that's the only way it is. Below, we have some more practice problems, and I'll see you in the next video.