Assessing alignment of the lateral cervical spine (neck) X-ray

this is Sal here again and I'm still here with my good friend dr. Mahadevan from Stanford University and in the last video we had looked at adequacy of x-rays which is for the neck which is you know is the x-ray good enough but now let's assume we have good x-rays now what do we look at the next step is to look at the alignment so we talked about the ABCs the ABCs of reading a cervical spine film and a starts with adequacy that we went over yes and the second part of a is alignment okay so we're still in a so nice alignment okay I was expecting something with a beat alright alignment alignment alright so this looks like this this is about alignment this is about alignment and there's four lines that we look at the first is the anterior vertebral body line okay av BL right over the exactly and basically what you're doing is you're trying to draw a smooth line that connects the anterior aspect the front of all the vertebral bodies and should be nice and smooth it's usually curved and all the points should sort of fit on that line nothing should be off of that line that would suggest that there was a problem there I see an interior as you just said means front exactly right okay the next line is going to the back of the vertebral body is the posterior vertebral by okay so not the back of the entire vertebra the vertebral body which is this boxy part right in front exactly okay so name the thing connecting a line up and down should be nice and smooth as you've drawn it and nothing should fall off that line though no piece of that vertebral body should fall off of the line you've drawn all right sounds good and then the next is we connect all the spinal laminar Junction so this is the spinal laminar line okay and it's where that sort of the the the lamina connects to the spinous process spinous process I sounds a gimmick a whole video about that spinous process if you look at the back of somebody's necks are those little bumps that you go okay and that's the various triangular things right here exactly okay okay so you that you're just connecting that line they're kind of the front of these triangles the base of these triangles so to speak exactly okay and then the last one and the last line is the spinous process tips and again we're just connect the top the tip of all these spinous processes little the little bony projections you can see if you look at the back of somebody's neck right right these two should generally fall in a nice smooth curve right and so the general rule of any of these don't aren't aligned the way that we've drawn it here it's it's it's a problem exactly exactly we call it subluxation or malalignment or misalignment okay and these are all suggests that there is a problem there which is a big deal because your spinal cord is going through there absolutely if you look between the two the green and the blue line that's actually where your your actual spinal cord runs right right right down there exactly I see I see so yeah you don't want that to get messed up all right so let's look at a few of these x-rays and see if we can if anything's wrong or if there's something wrong if we can spot it Thank You Sal now you know how to read cervical spine x-rays I'm gonna have you look at the first x-ray okay that's it and I'm gonna get sued for malpractice it's C all right so this one over here so let me just do the first one let me let me just go what what you told me to do so I'm gonna do with the the anterior side of this vertebral body exactly I'm learning the words to [ __ ] like a doctor okay so I'm going to draw a line here okay that looks pretty good yeah that looks decent that was I'm kind of let me see this is still looks decent and I know that that doesn't look great with this count I mean this looks like a it got shifted over a little bit absolutely huge it's not a huge shifting but it's enough to that it's not easy to draw like so that was right you're absolutely right and in fact sometimes it's very subtle and you picked up a very subtle abnormality but again even though it's subtle on the x-ray it could be serious for the patient so you potentially saved their spinal cord and and their lives by picking up an injury like that good making me feel all right very good okay so that's just it's literally something as subtle as that is what you're looking for exactly again it should be a nice smooth line or a nice smooth curve and as you can see at that Junction it's no longer smooth now you have to look at the other lines use any one of these that you don't align that's enough to say may do something else exactly and that's a great important teaching point which is if you see any abnormality on a plain film on x-ray like this you stop and you protect their cervical spine and then you get a more important study or a better quality city like a CT scan fascinating although if I do look here it does look like we could have done the the the pv BL and it looks like that also is is a little off too absolutely I won and okay well looks like it looks get a few more great I want to I don't want to focus too much on my first victory all right so this is so it's clear that this person is facing this way I can see their teeth alright so let's see let's see what we can do here can I give it a shot at least please okay so let's um the AV BL it looks pretty good I this this is well that looks close Alex close I agree and and it potentially again you've got it you've got a very keen eye and you might have picked it up but most people might have a gift you might have overlooked that I was almost right let's try other the other the other lines here so this is the this is okay so this one is more obvious this one is more obvious that there's kind of that disconnection right over they exactly and this is the P V BL or the posterior vertebral body line you can see clearly that line is not smooth it doesn't connect and so there is a problem right there at that Junction okay okay alright and so then we have this this last one right over here let me see what I can do let me see you want to lose my streak alright so anterior side this actually looks pretty perfect actually and in fact it is perfect okay let me let me try the next lines here this is the posterior lateral body line let me do that in a color that's easier to see don't use too orange on your magenta alright so this looks looking okay looks okay that looks okay I mean it laughs yeah I mean nothing obvious on that line I would say again you've got the keen eye but in this particular case I say it's fine and yes it's within the normal range as we say and so let me do the the base of those triangles let me do so this is a triangle right over here so that again you want to be a nice smooth curve everything should fall not curve so this it would be I would have to be a little bit generous with my curve to make it go to these guys down here exactly exactly and this is the spinal laminar line this is the third line of alignment as you can see to try to get those to work you could but they're not smooth like the other lines this is again another subtle finding but missing this finding because the first two lines are normal can be devastating for the patient right right until you you always want to err on the side of caution I mean if anything looks at even a little bit suspicious maybe another x-ray or yeah another x-ray another view like we talked about before or the definitive study is a CT scan or computed tomography I see I see very cool well well thanks for this is useful my pleasure