The pulley system of the flexors can also be scanned. So the patient's hand is placed on the table on the dorsom of the hand. And we're going to start by scanning the MCP joint which can be seen uh right here. So we can see the uh proximal failen uh right there. We can see the metacoupal head right here. This is the oloc plate within the joint. And this is the uh the flexor tendon with on top of it the A1 pulley. And the A1 pulley straps the tendon to the joint or to the bone uh and causes tendon stability but also of course lubrication because within the pulley system uh around the tendon we also have the tendon sheath. So let's follow the tendon to to distal. So this was the A1 pulley right there. Now we're going to look for the A2 pulley. The A2 pulley is in the middle of the proximal failank. Uh we can see that the tendon darkens a little bit anotropic due to the oblquity of the fibers. Um and the injury could be that there would be a pulley tearing. Uh so that the there is bow stringing which means that the tendon goes away from the bone. The tendon comes more to superficial. The tendon is not stabilized to the bone and that will increase distance from tendon to bone. So then the tendon is not strapped to the bone but the tendon has more a horizontal course and not following the curvature of the bone and that is an indication indeed that the pulley the A2 in this case has been torn. Of course we draw more pulley. So A1 A2 we can look at the A3 pulley we have a A4 pulley and in the end also the A5 pulley uh over the uh DIP joint. Uh after having checked the tendon to bone distance and longitudinal, we can also have a check in um in this transverse view here. We can see the convexity of the metacarpal head with the flexor tendon on top, a little bit of var plate in between. And we can see the tendon sheath and the pulley system on top. Follow uh we're going to observe the cross-sectional area of the tendon, but also the thickness of the pulley. Is it uh increased? Is it torn? And if it's torn then we might see the um yeah the uh the tendon to bone distance that that might increase. So in between the metacarpal head and the proximal failank we can see well no bone. So this means that this is the joint looking straight into the MTP joint. And now on top of the midshaft of the proximal failank we can see again the cross-sectional area of the flexor tendon with the pulley. And we're going to observe the tendon to bone distance, the cross-sectional area, do we see any fluids surrounding the tendon, and any changes to the pulley thickness?
