go on good morning this is lecture on chapter 4 of the elbow and this is in your positioning book and this comes from the ninth edition this first image we have is actually found on page 133 and it is figure four point one six and this is an AP elbow this is actually the distal humerus and the proximal radius and ulna that make up the elbow joint now as far as the anatomy this should be familiar to you all but there's this little acronym here the RC u T and what that means is that the radius articulates with the capitulum and that the ulna articulates with the trochlea and that's what actually forms that elbow joint is the radio articulating with the capitulum and the ulna articulating with the trochlea you can see we have the medial and lateral epicondyle that important landmark when we position not only for the elbow but when we talk about AP humerus those become important we have two little depressions on here you have the coronoid fossa and the radial fossa and unlike we said we have the head of the radius this is actually the radial tuberosity right here this is the proximal radioulnar joint in here and then we have the trochlear sulcus or the trochlear groove and then this is actually a right elbow with the hand supinated palm out as if you were in anatomical position and then the radius would be thumb side and the ulna actually falls on the fifth digit side if we look at the elbow in a lateral view this also is on page 133 and again this is the distal radius proximal ulna I'm sorry distal humerus proximal ulna and the radius this is just looking at it from a side view so you can see that we have the radial head right here we have the gun the electron on process right here or the semi semilunar not so clear not right in here and then you the ridges of the capitulum and the trochlea on top of each other between those and this groove right here this semilunar notch or trochlear or not we're going to talk about the three concentric arcs that we need to look for to make sure that we have a perfectly lateral elbow okay so again anatomy is very important to what we do these three concentric arcs that they talk about basically you have the the trochlear sulcus which is one and three concentric arcs meaning three three circles or three arc shapes that you look for to make sure your elbow is lateral you have the outer ridges of the capitulum and the trochlea on top of each other and then we have the trochlear notch or this depression right here or the semilunar notch is some refer to that and then you can see radiographically how you can see these three concentric arcs here all in a row you can see radiohead right here this faint area is the radial tuberosity got the proximal radioulnar joint and then the elbow itself and then this is the electron on process and this is distal humerus and they talk about the posterior depression on the distal humerus is the olecranon fossa and the olecranon process of the ulna fits into that olecranon fossa when the arm is fully extended and it says that soft tissue detail is depicted by specific pads that are located within electronic fossa and it's important in trauma diagnosis of the elbow joint and we'll look at those fat pads in just a minute but on a lateral elbow especially this is where the area right in here right back here we tend to look for fat pads because a positive fat pad sign is indicative of trauma or injury and typically there's a fracture when when you see a positive fat pad sign if we look at the AP elbow as far as Anatomy this is on page 134 and you can see with letter A here this is the medial epicondyle which tends to be more prominent than the lateral epicondyle and the lateral epicondyle is right here F is the lateral epicondyle so not as prominent as this one if you palpate the inside of your elbow this side with your arm extended out palm you can definitely feel the medial epicondyle much more so than the lateral epicondyle and then letter B here we have the trochlea see we have the coronoid tubercle d is the radial head right here radiohead redeal neck would be right here in radial tuberosity is right here he we have the capitulum head flake is the lateral epicondyle not as prominent and then H is the electra Nam process that you can kind of see coming through and that sits in Akron on fossa now that is an AP elbow how do we know because there is superimposition of the radial head neck and tuberosity over the ulna in AP and then if we look at the lateral we can um we can see starting with we ended with H letter I here is the trochlear sulcus Jay is the trochlear notch and in here this second little line in the concentric arc and then k is actually the double outer ridges of the capitulum trochlea so when they talk about those three concentric arcs that's what you're looking for the trochlear sulcus the triply are notched and the double outer ridges of the capitulum okay and that is a dural elbow again when we look at fat pad signs we're gonna be looking in here and we're gonna be looking back here when we look for these fat pad the elbow joint itself is a synovial joint meaning that there's synovial fluid in there and it is a Dyer throttle joint here you can see the proximal radioulnar joint that is a pivot type meaning it allows us to pronate supinate our hand and the elbow joint is a gangly mess or a hinge type joint meaning it can open and close like a door allowing us that hinge like motion as far the rotation that we have with the elbow when we look this is an AP right elbow alright and there's no rotation on this because the radius and the oume are partially superimposed that's how you know it's an AP you can see the radial tuberosity the neck radius in the head are partially over the ulna and then when we look at the elbow this left elbow now why they do right left right I'm not sure but this is definitely a right elbow this is a left elbow so the radius is also again arm extended palm up this has external rotation or lateral rotation and when we do that lateral rotation or external rotation you actually have the radial head neck and tuberosity become free of superimposition from the ulna so this space right here that you see is indicative that this is an externally rotated elbow a 45 degree external or a 45 degree lateral Blake and then when we look at this one this is actually a right elbow and this is internal rotation or medial rotation so a 45 degree medial or a 45 degree internally rotated elbow and how we know that you can see that now the radial head and neck is completely superimposed by the ulna but we can actually see the coronoid process here and it sticks out and that's one of the things to know if you have an internal versus an external on the external the radial head neck and tuberosity of free of superimposition and on the internal the coronoid process is in profile alright those fat pads I was talking about these are actually found on page 137 and we have the anterior fat pad which is labeled by letter C we have the posterior fat pad which would be back here and we have the supinator fat stripe which is up here by letter E okay and typically on a lateral elbow this is where you would see a positive fat pad sign now you can see in this there is a broken electron on process on here you see the fracture lines right there okay and you can actually according to the book you can see a positive anterior and posterior fat pad [Music] in the supinator Strait but I'll be honest I don't it's very hard to see these you can kind of see right up in here where that dark area is and then this dark area here now that probably is blood in the tissue but a lot of times when you see a positive fat pad sign that's what it looks like an area of increased density or decreased brightness a little bit darker in there and a lot of times when you see a positive fat pad sign which is very hard I do not see them on this but if we saw a positive fat pad sign it's usually indicative of injury meaning this should produce a fat pad sign that's because of the electron process being broken like that but it could be with the labeling that we're not really seeing that very well you can kind of see here with the capitulum and the trochlea see how they're not perfectly superimposed so you're not getting those three cancer arcs like we should not to mention you're not going to get that third arc or the trochlear notch or semilunar notches because the electron process is actually broke so you've got half of the notch here and then the other half is over here because of this fracture okay so a positive fat pad sign is indicative or fracture now we will get into the positioning of the elbow and for the elbow there are actually four physicians that are considered routine for the elbow we have an AP a 45 degree internal or medial oblique meaning that the arm is rotating towards midnight or towards the body we have a 45 degree external or lateral Blake which is meaning that the the arm the extended arm is rotating away from the body and we have a lateral now the ER I see basically when I was saying to you that the radial head neck and tuberosity were free of superimposition that just means that on the external the radial head neck and tuberosity are free of superinten and on the internal that's where we demonstrate the coronoid process in profile the technique for all of these images is 70k VP at 2mass now ideally when your patient comes in they would be able to fully extend their elbow but if there's an elbow injury sometimes that is not possible okay but in theory we would like a fully extended ap elbow how do we know it's extended in completely AP epicondyles that are on a humerus the medial and lateral epicondyle should be parallel to the IR so you have to palpate that area and make sure that they are parallel to the IR that there's no rotation in the elbow joint itself and the Centurion this is not difficult it is actually mid elbow now if the patient can't fully extend their arm then you have to do to any views in a partially flexed position when they can't extend the elbow you have to do one with the humerus parallel to the IR and then a second one with the forearm well to the IR okay so if they can't straighten it whatever the injury is you end up having to do two of the APS one with the forearm parallel one with the humerus parallel and this is actually something they love to ask on job interviews they want to see if you can critically think and a lot of times though they'll say to you let's say you have a patient come in with an elbow injury and they cannot extend the elbow completely what would you do and they're looking for you to say well I would take two a ps1 with the humorous parallel one with the forearm parallel and I would evaluate those and then go from there that's typically what they're looking for and then with both the central ray is perpendicular again to mid elbow so that's considered trauma if the patient is unable to fully extend the elbow that is what we would need to do now on the AP to compare them this is an AP with the arm fully extended okay so arm straight out injury but not that they can't straighten their arm out and again remember we said that the radial head neck and tuberosity superimposed by the ulna that's how we know it's an AP and then we look at the lateral and medial epicondyle and we want to make sure those are parallel to the IR these two are the views when the patient could not straighten their arm so this one was done with the humerus parallel to the IR central reynad elbow this one was done with the forearm parallel to the IR century again mid elbow okay so when the patient cannot fully extend this is what they would look like you can see there's a little bit it looks a little bit elongated on the humerus when that's parallel and this radius and ulna look a little bit elongated when the forearm is parallel so once you do the AP then we go on to our own Blake's and we do two O Blake's both at 45 degrees we do a 45 degree lateral or a 45 external oblique meaning she is rolling away from midline her arm is rolling backwards so she's externally rotating and on that one this is the one the external will place the radial head neck and tuberosity free of superimposition this one typically when the arm extended if you simply supinate the hand or turn your hand palm down that will typically put your elbow into a perfect 45 degree medial or blank or internal oblique and this is the one that allows us to visualize the coronoid obsess in profile okay so 45 degree medial Oh Blake we simply supinate I'm sorry pronate the hand and on the 45 degree lateral or external of like you're literally having to roll the patient backwards sometimes they have to actually lead their back backwards because you can't usually just turn your arm you can't extend it that far sometimes if you lean their shoulders back that actually helps now what would the images look like first we'll look at the external rotation so this is the one where they lean back and you kind of hold their arm out so on this 45 degree lateral or external oblique again the radial head neck and tuberosity are free of superimposition in the lateral epicondyle and the capitulum are in profile okay so this is a right arm fully extended patient rolling backwards or rolling away from midline to make the radial head neck and tuberosity freest from position and then on the internal or the media lobe like this is where the hand is simply pronated this one will actually throw the coronoid process into profile right here you can see the electrode on process back here Radiohead is right here and neck that's completely superimposed but this coronoid process of the ulna sticks right out and that's what we're looking for on the 45-degree medial or internal oblique then we move on to the lateral elbow and with the latter whoa elbow must be flexed to 90 degrees okay flex um the elbow 90 degrees and the humerus and the forearm are parallel to the IR so you want to make sure you have a really good 90 degree angle between the forearm and the humerus okay one thing in the central Ray is still mid elbow and the technique for all of these with 70 kvp at two mass now let me go back for one thing that I wanted to tell you that I'm not really sure I did if we go back all of these positions the patient has to have not only their arm extended but for all of these they have to have the shoulder the elbow and the wrist all in the same plane which means the patient has to either slouch in the chair or you need to raise the table up so that the wrist the elbow and the shoulder are all in the same plane okay so either of two ways you can do that you can either raise the table so it brings the arm up equal with the shoulder or you can agent slouch down in the chair like slide their their rear-end forward so that they slouch down all right in the center a on all of these is mid elbow joint and the technique is vini kbp at two mass again for the medial and lateral Oh Blake or the 45 internal and 45 external notice her shoulder her elbow and her wrist are all in the same plane that's very important for all of these images so whether she's flout down in the Cho or they raised the table up either way as acceptable as long as everything is in the same plane all right and then same thing for the lateral when we do the lateral so patients slouched down elbow is at a 90 degree angle the humerus is at a 90 degree angle to the forearm they're still slouched central Ray is still mid elbow and they tell you on the lateral the mid elbow is approximately one and a half inches medial olecranon process so what they're saying is if you palpate the eleven on process you come one and a half inches medial or towards the middle of the elbow so from the electrode on process you're coming in to the center okay marker placement let's go back and look and see where they have her for the AP because it should be lateral to the part which it is so this is a right marker and it is lateral because the the thumb side would be lateral or the radius and notice the mark replacement now up until this point everything has held fingers up now this is actually hanging humerus up okay so the next few things that we look at this week we are going to be hanging humerus up so forearm hyung fingers up and that was the last thing we talked about now we're in elbow fingers would be down here shoulder up here so it hangs humerus up so this marker placement is correct on the AP when we look at field legs there was no real marker in the in the images but you can see on this medial Oh Blake this is a right arm and they have the right marker medial to the park so ideally the marker would be on this side and it it is placed correctly you can see that when this is it would read properly with the humerus up so that is correct but it should be on the other side same with this one this marker should be on the other side let's see if it's in the images yes it is in the image here but ideally that marker be up here or at least on this side the lateral aspect the elbow so marker placement on that one is correct because this is the internal rotation that demonstrates the coronoid process in profile and the right is on the lateral aspect humerus up so that one is correct and then when we look at the lateral it does hang humerus up so in this previous picture the way they have the marker is not correct because if you hang that humerus up that right is gonna be laying down correct like if you imagine that film hanging this way where the top is here and the bottom is here then that marker is actually sideways so that Margaret just be moved let me try and draw it for you that marker should be moved on this side and it should be so that they would hang that way okay so markers should be on that side and then when we look at the image it's not bad at least it's reading correctly but it still would be better over here that would be better marker placement to place it to go better marker placement would be where it was and then reading like that okay all right so again on this particular image let me go back to the pointer you're looking for the three concentric arcs the capitulum in the trochlea the trochlear sulcus right in here excuse me you're looking for those three concentric arc the elbow notice that the humerus it is a is at a 90 degree angle to the radius and the ulna so that actually is a really good lateral elbow now you can see there they just barely got the soft tissue on there you can see soft tissue here where the elbow creases and if we look back at the image prior we see definitely that they've got all of the soft tissue it just looks like on this particular image they came awfully close you don't ever want to not include the soft tissue on an elbow because sometimes you'll see bleeding into the tissue which is pretty much indicative that something is going on in there so you want to make sure if the radiologist sees blood in the soft tissue that he's looking a little bit for a little bit deeper at any issues that might be in there already and that takes us to the end of elbow if you look in your book actually on page starting on page 173 and 174 there are some additional views that they show you if there is trauma for the elbow when they're looking for the coil method a lot of times this these are done for pathologies in the area of the radial head or the coronoid process and it's also the coil map that also works really well if the patient can't extend their elbow fully for the obliques and then on 174 when there are radiohead or radial neck fractures there are some different views that they show you of positioning the hand whether the hand is supinated lateral pronated or internally rotated it can demonstrate some radiohead fractures and radiohead fractures on a patient are horrible they're not able to typically they're not able to pronate and supinate their hand because that's that mo radial ulnar joint that allows for that and when there's a radial head fracture they're limited in that movement and usually they're in a lot of agony when the patient is suffering from that so make sure you look at those additional views there and we will meet up in the live and discuss have a good day