Scratch Test

00:00 So, what I tend to do is, have you heard of a scratch test, which I don’t know what are you doing in your exams. Can I get you to lie down again for me? I remember one of my consultants teaching me this. You probably don’t do this because you are really young.

00:14 But if you’ll imagine the train track and someone is tapping on one side because that transmission is going through the train track. You can feel it further down. It’s the same principle. So because all of this is air and you’ve got a rib overlying a relatively dense structure like the liver, what you can do is if you take your stethoscope, feel for the bottom part of the rib and you put your stethoscope on. If you kind of scratch up when you notice that you can hear the scratching.

00:41 That’s the liver edge.

00:42 Yes, he did. He still teaches that.

00:47 Does he? Yeah.

00:48 I think that’s the most useful thing that I’ve done because I find it quite difficult to palpate out livers. And if you’re tapping for shifting dullness, do you have to be parallel to the bed of your finger going down? Because a lot are doing it like that but is it the correct way to do like that? Say that again. So, why not -- Your finger, the one that you have on the abdomen must be parallel to the counter base. Because if I’m doing it that way, I’ll give you an exam and I could say, “Well, how do you know that it’s not the tip of your phalanx rather than down here where you’re feeling the percussion note?” So yeah, it needs to be parallel. It’s fine. You can get up again.

01:33 I think it was about the liver. See, you need to be tapping out the borders, and how big should the liver actually be? You tell me, how big should it be.

01:42 Four fingerbreadths, about 10-12 cm. Above the costal margin. Where does your liver start in your chest? Yeah, it’s about your sixth anterior but it’s around T4. So it goes really -- Tell me why we have to tap it out from the top because if it’s a woman, it’s difficult isn’t it? Again, it’s different to what you do in clinical practice, but ideally yeah you’re supposed to tap it out and I always start on the chest, go down. It’s unlikely you’re going to get woman for an abdo exam if it’s something that you need to percuss out anyway. So if you percuss it down you’ll go from resonant resonant resonant because you’re going lung, lung, lung. Then when you get to liver, you’ll notice the percussion note changes.

02:24 Spleen has to be three times its normal size to be palpable. The liver even in thin persons, can you feel it and know pathology? Someone told me that even in thin persons you'll never feel the liver unless there’s something wrong, but I seem to find that you can feel it -- I’ve felt it in people that are otherwise well. Okay. Thank you.