hello everybody and welcome back to another Anatomy tutorial today we're going to be looking at the bones of the wrist as well as looking at the alignment of the wrist on a wrist radiograph we'll look at the three main projections that make up our wrist series namely our AP View our oblique View and our lateral view or lateral projection that's really good when assessing alignment of the wrist let's start by having a look at our AP view we can see the carpal bones lie between our metacarpals of the hand and our radius and ulna of the forearm a radius has this broad distal portion here and our ulna has a narrow distal portion that's opposite to what we saw in the elbow where the ulna is the broad portion and the radius has that small radial head in the annular ligament you can see that the carpal bones are formed in two separate rows we have our proximal row four bones in the proximal row of the carpals and our distal row here now many of you would have learned to mnemonic when trying to remember the names of these bones and I encourage you to go a step further here and try and remember the bones by their shapes and their relationship to other copper bones within the wrist in order to be good at assessing risk radiographs you really need to understand what normal looks like what is the normal morphology of each bone and what is the normal relationship with other bones within the wrist so let's start by naming the proximal row we'll start laterally now this is our lateral side we can see our Thumb in the anatomic position is lateral we know that our thumb is on the same side as the radius an easy way to remember this is that your thumb can do a radial movement just on the same side as the radius so proximal row lateral bone is our scaphoid bone one of the most important bones to look at when looking at a wrist radiograph you can see how scaphoid bone scaphoid meaning both in Latin is shaped like this it actually heads from proximal to distal it heads from posterior to anterior it has this anterior tilt and we're going to see that on our lateral radiographs the fact that it tilts so much in the wrist mean that it superimposes itself and makes it quite difficult to assess this distal portion well but we really need to be able to trace the cortex of this scaphoid bone ensuring that the nerve fractures is a really common fracture site of the scaphoid then medial to our scaphoid is our lunate bone lunate meaning Moon shaped you'll see on the lateral view that the lunate bone is Crescent shaped like Moon shaped and it actually cups the capitate above it then more medial to our lunate is our triquetrum our three cornered bone it's got this triangular shape and just anterior to that triquetrum is our pisiform which means p-shaped it's technically a sesamoid bone it lies within our flexor copy alnora's tendon here and there's our pisiform which again lies anterior to that triquet room then our distal row of carpal bones will start now immediately and head our way laterally you can see our hamate bone here and our handmade bone is quite unique it's got a projection of bone that we can see we're catching end on here called The Hook of the hamate then lateral to the hamate is our main bone our capitate bone capitate meaning head shaped kind of see a head shape here but the easy way to remember this it's the biggest Central bone the main bone the capital bone it's all capitate bone then we have paired bones here we've got our trapezoid bone and our trapezium bone many people remember trapezium under the thumb it's a good way to remember it but we also have our triquetrum so some people get confused by naming this a triquetrum so the best way to remember that is that our thumb and our scaphoid trap the two bones between a trapezium and we go to four this is be trapped between the scaphoid and the thumb so trapezium and slightly medial to that our trapezoid bone then you'll see that there's no actual bones in this space above the ulna and this is what's known as our triangular fibrocartilage complex what it does is if we were to put pressure on our wrists say doing a handstand it would divert some of that pressure away from this thin ulna into the radius here this broad base of the radius we don't want direct pressure onto this ulna now it's made up of many structures but the main components are our ulnar carpal collateral ligament Humalog which is a triangular shaped piece of cartilage here and then we've got a triangular fiber cartilage disk proper here which makes up this triangle shape here we mustn't see bones floating within the space we want to see a good space here so let's move on to our oblique View and one of the major advantages of the oblique view is looking at our scaphoid bone can you see how scaphoid bone heading here you can see how from the proximal portion to the distal portion the scaphoid Bone Heads anteriorly This is Our anterior this is our posterior next to the skateboard is our lunate bone you can see that Crescent shape like that our Luminate bone which is cupping our capitate there then medial to our lunate bone we've got our triquetrum here and our triquetium you can see just anteriorly to that there's our pisiform it's quite difficult to see on this projection our handmade bone is in our distal carpal row and most medial bone with our handmade hook which is quite difficult to see on this projection and then also I'll capitate bone here sitting within that cup of the lunate we have our trapezoid bone as well as our trapezium bone that's under the thumb now let's move on to our lateral projection and try and identify some of the bones we can see our ulnar bone here and our radius heading out distally there the easiest bone to identify in this View at least for me is a lunate bone because we can see that Crescent shape there heading down and articulating with the radius now if I go back two slides to our AP view you can see our radius the distal articular surface here is kind of scalloped two separate fossa there the first that articulates with our scaphoid and the second that articulates with the lunate bone you can see how the lunate is actually slightly more proximal than our scaphoid bone so in our lateral view when we're looking at it our lunate bone comes just below our scale for it then cups like that articulating with our radius I'll scale for it Bone Heads from posterior to anterior as it heads more distally we can see how scaphoid bone projecting anteriorly here wrapping its way around like that follow the cortex of it there the more radiographs you look at the better you're going to be at outlining these bones you can see in our lunate is our capitate you can follow the capitate around it should be sitting nicely within the lunatic we've got this location there you'll see that this ball in cup kind of view won't be there the lunate will either be facing forward or facing posteriorly you can see here our PC form anteriorly and a good marker for whether a lateral is a true lateral is by trying to get this anterior surface of the pisiform to lie between the anterior surface of our capitate bone and the anterior surface of our scaphoid bone so here maybe we've got a little bit too much supination and it's for that reason that we don't see our triquetrum sticking out posteriorly very well here normally we can see the back or the posterior portion of that triquetarum sticking out and here we can see our trapezium here as well as our trapezoid it's quite difficult in these projections to outline those individual bones it's quite difficult again to see our handmade bone in our distal row of the carpal bones so another thing to appreciate here is that our carpal bones aren't like a brick wall where they're stacked perfectly in a flat line on top of one another they actually are quite concave anteriorly they cup forward that's because we've got loads of flexors running through the front of our wrist unit and provide space for those tendons to run through as well as our median nerve and arteries to run through so we need to create some space and that's what's known as our carpal tunnel now this isn't a very common view to do of the rest but it really gains an appreciation for that concavity in the wrist this is the anterior surface of the wrist here we can see our thumb on this side and below our thumb is our trapezium our trapezium projects anteriorly like that you can see how it sticks out of the wrist on that same side in our proximal row is our scaphoid bone here's our skater it's on this side the lateral side we've got two bones projecting anteriorly we've seen how the scaphoid projects anteriorly and our trapezium so scaphoid and trapezium are here on the other side we've got the hook of the hamate bone in our distal row as well as our pisciform our p-shaped sesamoid bone that project anteriorly as well then we have a retinaculum that connects these anterior structures together and provides a tunnel a carpool tunnel here for the structures of the wrist to run through so you can see how that concave shape allows for this space to be formed we don't want tendons having to go over bones in direct contact and as we move our wrist like that would then give us a tendinopathy or a tendonitis by those tendons having to rub over the bones this provides a tunnel for those tendons to move freely in the middle here would be our capitate and below that would be our lunate bone here would be our triquetrum behind the pessiform bone so let's move on to another view that you may see within your practice and this is an only deviation view they've got the patient to move their hand like that and that what that does is it brings our skateboard up and round and allows us to look at the length of the scaphoid you saw in our AP view the scaphoid as it goes forward it projects over itself we get superimposition of the scaphoid on itself here as we only deviate we bring that skateboard around and we can see the whole of the scaphoid there now why this Gateway is really important is because as our radial artery comes around it gives off a branch towards the scaphoid and we've got that Branch then supplying the distal portion the waste and the proximal portion of the scale for it if we were to fracture within the waist or the proximal portion of the scaphoid we don't have a dual blood supply here and we can get avascular necrosis in this proximal portion of the scaphoid again as we head more approximately the chance of avascular necrosis increases and the chance of mold Union when we fracture this scapular bone increases as we head in proximally we can see here that the skateboard has a distal pole and a proximal pole and that's separated by what's known as the waste of the scaphoid this is our most common site for fractures in an adult so it's really important to see the Integrity of the cortex around that portion if pain doesn't allow a patient to do that we can take an angled view a 30 degree angle View at the scaphoid as well to give us that end on look at the scaphoid so now we've covered the actual bones within the wrist let's look at the alignments of the wrist now the first thing that you want to do is assess the space between the wrist bones themselves and what we want is a generally even space between the bones and again the bones aren't laid like bricks on top of one another with perfect spacing when we look at a particular view the Bones have formed this complex shape around one another so some of the spaces like between the trapezium and the trapezoid bone we're not going to see that space very well but the spaces that we can see this distal row articulating with our metacarpals as well as a space to say between our scaphoid and our capitate here we can follow them all the way around make sure that we have even spaces we've not got obliteration of those spaces or expansion of those spaces we can see here that this is normal our spaces are even we haven't got any disruption of the spaces there we can then look at what's known as the carpool arcs of the rest we have a carpal Arc here coming along the proximal border of our proximal carpal bones here and we should see a smooth Arc forming all the way around if we've got fractures or dislocations we could have disruption or step up or step down deformities of this carpal Arc we can then look at our distal row we can see there is a nice smooth Arc between the capitate and our hermate there some people also continue the arc between the trapezium and trapezoid bones making sure that that space is consistent right the way through the wrist then we can move on and look at what's known as our radial inclination I'm going to draw on this slide and we can see where we would measure the angles here in the radius so if we were to take our radial bone here our radius and draw a perpendicular line to the shaft of the radius we can then draw a line along that articular surface there and measure this angle here that's what's known as the radial inclination Angle now that angle should be between 20 and 25 degrees if we are dealing with something in the order of less than 15 degrees we should really suspect some form of distal radial fracture here where we've lost that angle within the radial shaft that's known as radial inclination if we have an angle that's more than 25 degrees then we could be dealing with a deformity known as Madeline's deformity so now we've looked at the radial inclination on an AP view we can also look at the volar radial inclination our roller surface here anterior surface now when we look at the radius here on our AP view you can see how the scalloping of that end of the radius here allowing for articulation with the lunate in the scaphoid creates an articular surface here and then we have this radial styloid heading upwards when we're looking at our lateral view trying to get our volar inclination we want to look at this articular surface here when measuring the roller inclination so here we can draw again a line perpendicular to the shaft of our radius and we can see here is the articular surface of that radius there so that is the angle we measure we don't follow the radial styloid up here and measure the angle that way we want to measure this angle here and again we want that angle to be between 10 and 20 degrees A disruption in that angle we need to look for pathology reducing or increasing that angle the next thing we can look at is what's known as ulna variance we're looking at the radial articular surface and we want to look at the radial ulnar joint here at the variation between the radial surface and the ulnar articulating surface we want the difference between these two surfaces to be less than 2.5 millimeters if the ulna is deviated this way it's known as positive ulna deviation if it's deviated approximally it's called negative only deviation there are multiple things including fractures that can cause the ulnar variance to change either positive ulnar variance or negative ulnar variants next we're going to look at the lateral view to figure out our alignment of the rest again we can outline our Luminate brain here we can see that our capitate sits nicely within our Luminate let me try and get the capitate accurately here and we want to capitate the lunate our metacarpals and our radius to be nicely stacked on top of one another we can have this boiling cup disrupting when we have dislocation of that lunate so it's really important to see that capitate sitting within the lunate and you want this line to be generally well aligned well stacked on top of one another and the last piece of alignment that we're going to look at is also involving the lunade so let me draw outline of this lunate I'm drawing this with my mouse I'm not so accurate here we go is our scaphoid bone that we looked at earlier coming around there's the bottom of our scaphoid coming all the way around like that you can see that our Luminate is upright and we can draw a perpendicular line through our lunatio let me try and draw this straight from a perpendicular line through our lunate we can then draw a line through the shaft of that scaphoid bone you can see how the scaphoid goes from posterior to anterior here so we want to draw a line like that and this angle here between our lunate and our scaphoid should be between 30 and 60 degrees we don't want that scaphoid to move forward like this or we don't want a fracture within the neck of the skateboard that Muller lines the lunate and the scaphoid so there we have it a Whistle Stop tour through the bones of the wrist as well as mentioning some of the things you want to look at in terms of alignment within the wrist so I hope this has helped my encouragement to you is go and learn the bones by name and by shape rather than learning a mnemonic to remember the order of the bones and just one thing before we go I've created a monthly newsletter where I share 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