The AVBL, PVBL, SLL and spinous process tip lines must all be smooth curves. First look from the AVBL then move across. If the line is not smooth, it signifies a misalignment.
What is assessing alignment if the neck?
A very informative video on the assessment of the alignment of the lateral cervical spine. Definitions are given which are the "A's" which are the beginning of the assessment. These are 'Adequacy,' followed by 'alignment,' and then we take a look at the 'AVBL' which stands for anterior vertebrial body line, 'PVBL' which stands for posterior vertebrial body line, 'SLL' which is the spinous lamenar line and finally the spinous process tips. These are all the assessments made in order to determine whether a person has good spinal alignment and/or if their spinal cord is at risk or not.
adequacy means alignment. avbl is the front of the spine section pvbl is the 2nd of the spine section sll is the back of the spine section . if these don't curve nicely if there are any disturbances then support the spine cord and protect then investigate further
this is sal here again and i'm still here with my good friend Dr maja Devon from Stanford University.
In the last video we had looked at adequacy of x-rays for the neck, is the x-ray good enough?
But now, lets assume that we have good x-rays, now what do we look at?
Dr Devon: The next step is to look at the alignment, so we talk about the A, B, C's
The A, B, C's of reading a cerebral-spinal film. A starts with Adequacy, that we went over, and the
second part of A is Alignment.
Sal: Ok, so we're still in A, I was expecting something with a B...
Alright, Alignment. Alright, so this looks like 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. Ok, AVBL right over there.
Exactly, and basically what you're doing is trying to draw a smooth line that connects the anterior aspect,
the front of, all the vertebral bodies, it 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, and anterior as you just said means front.
Exactly. The next line is going to the back of the vertebral body is the Posterior Vertebral body.
OK, so not the back of the entire vertabrae, the vertebral body, which is this boxy part right in front.
Exactly. So, same thing, connecting a line up and down, should be nice and smooth as you've drawn it,
and nothing should fall off that line, no piece of the vertebral body should fall off of that line as
you've drawn it.
Alright, sounds good. And then?
The next is we connect all the spinal laminar junctions. So this is the spinal laminar line, and it's
where, sort of the lamina connects to the spinous process.
Spinous process, sounds like we could make a whole video about that...
Spinous process, if you look at the back of somebody's neck are those little bumps that you can see...
Oh, ok, so these triangular things right here...
Oh, ok, so you are just connecting that line, kind of the front of these triangles, the base of these
triangles, so to speak.
OK, then the last one?
The last line is the spinous process tips. And again, we're just connecting the top, the tip,
of all the spinous processes, the little bony projections you can see if you look at the back of
And these, too, should generally fall in a nice smooth curve.
Right, and so the general rule is that if any of these aren't aligned the way that we've drawn here,
it's a problem.
Exactly, we call it subluxation, or malalignment, or misalignment...
And these all suggest 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 green and the blue line, that's where your actual spinal cord runs.
Right, right, right down there.
I see, so you don't want that to get messed up.
Alright, so let's look at a few of these x-rays and see if we can, or if anything's wrong, if we can
Actually, Sal, now that you know how to read cerebrospinal x-rays, I'm going to have you look at the
(Laughing) OK, let's see, so now I'm going to get sued for malpractice! Ok, let's see, alright...
This one over here, so let me just do the first one. Let me just go over what you told me to do.
So I'm going to do the anterior side of this vertebral body...
I'm learning the words, too, talking like a doctor...OK, so I'm going to draw a line here.
OK, that looks pretty good.
That looks decent, this still looks decent, and I don't know, that doesn't look great, would this count?
I mean, this looks like it got shifted over a little bit
I mean, it's not like like a huge shifting, but it's enough to, that it's not easy to draw a line, so,
so I was right?
You're absolutely right, and in fact sometimes it's very subtle. You picked up a very subtle abnormality,
but again, even though it's subtle on the x-ray it can be serious for the patient, so you potentially
saved their spinal cord and their lives by picking up an injury like this.
OK, very good. So it's literally something as subtle as that is what you're looking for.
Exactly. Again, it should be a nice smooth line or nice smooth curve, and as you can see,
at that junction, it's no longer smooth.
You don't even have to look at the other lines, you just, any one of these, that don't go on a line,
that's enough, you say, hey, do something else.
Exactly, and that's a great important teaching point, which is if you see any abnormality
on a plain film, or on an x-ray like this, you stop, and you protect their cervical spine,
and then you get a more important study or better quality study like a CT scan.
Fascinating. Although if I do look here, it does look like we could have done the PVBL
and it looks like that also is a little off, too.
Well, let's look at a few more.
I don't want to focus too much on my first victory...
Alright, so it's clear that this person is facing this way, I can see their teeth.
So let's see what we can do here. Can I give it a shot again?
So, AVBL looks pretty good. This is, well, that looks close, it looks close...
I agree, and potentially again, you've got a very keen eye and you might have picked it up,
but most people might have overlooked that.
Ok, so let's try the other lines here. So this one is more obvious, this one is more obvious, there
is kind of a disconnection right over there.
Exactly, and this is the PVBL, or the posterior verterbral body line, and you can see clearly that line is not smooth, it doesn't connect,
and so there is a problem right there at that junction.
Ok, ok, Alright, so we have this last one right over here. Let's see what I can do, I don't want to
lose my streak...
Alright, so anterior side, this actually looks pretty perfect, actually.
And in fact, it is perfect.
OK, let me try the next lines here.
This is the Posterior Vertebral body line
Let me do that in a color that's easier to see, magenta, alright. It looks ok, ok, it looks ok, I mean
nothing obvious on that line.
I would say again that you've got the keen eye, but in this particular case, I'd say it's fine.
Its within the normal range, as we say.
Ok, and so let me do the base of those triangles. Let me do, so this is a triangle right over here...
Again, you want to be a nice smooth curve, everything should fall on that curve...
So this, 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
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