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This patient presented with

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a left C6 radiculopathy.

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So, when we look at this image, on the left

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hand side is a non-contrast T1-weighted

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image performed in the axial plane.

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So, when you look at this, it

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can be pretty intimidating.

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But here's some ways that I

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use when I look at the neck.

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So, the neck is not 100 percent symmetric,

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but what I do like to do is I like to

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take a line and draw it down the middle.

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And then I like to compare the

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right side with the left side.

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Now, this patient has a left C6

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radiculopathy, so that tells me that

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I'm looking at the cervical spine.

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Now, the patient already had a cervical

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spine that didn't show any evidence of a

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disc herniation or a disc bulge, so they

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were looking at something more peripherally.

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So specifically, the patient ended

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up getting a brachial plexus MR to

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look at a left-sided mononeuropathy.

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So, when I look at this, the first thing that

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I do is I need to find the brachial plexus.

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So, I go back to those anatomic components

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that we talked about in the initial lecture.

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So, on the normal side, what I have to

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do first is, because we're at the level

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of the supraclavicular plexus, is I have

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to find the anterior scalene muscle.

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So there's the anterior scalene muscle,

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right here, and I'll just put a little "A" there.

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Then the next muscle that I look for

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is located right here, and that is the

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middle scalene muscle, the posterior

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scalene muscle, so I'll put a "P" there.

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So between the anterior and the middle scalene

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muscle is the plane of the brachial plexus, so I

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know that's where the brachial plexus has to be.

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And also, if you look at this, if you

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look at the anterior scalene muscle,

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just look at this angle right there,

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it sort of has this acute angle.

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Now, that's what's normal in this patient.

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Now, let's look at the opposite side.

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So the first thing that I have to look for is

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I have to find that anterior scalene muscle,

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and here's that anterior scalene muscle here.

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And the posterior scalene muscle is

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just going to be posterior to it.

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And then between the plane of the

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anterior scalene muscle and the plane

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of the posterior scalene muscle right

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here, we can see the brachial plexus.

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That's the supraclavicular

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portion of the brachial plexus.

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But if you even look more peripherally, we see

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this mass right here, which is located along

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the margin of the anterior scalene muscle.

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When we give contrast, we can see that

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this mass is homogeneously enhancing.

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Now, some of the challenges that you can

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get into, is this a lymph node, or is this a

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mass that's arising from the brachial plexus?

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It is in relatively close proximity

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to a lymph node, but it's not in the

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exact proximity to the lymph node.

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And how do we properly localize

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this mass to the brachial plexus?

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Well, again, take a look at the

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anterior scalene muscle on the right

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side and look at this lateral margin.

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We can see how it's kind

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of narrowed and rounded.

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But notice how this mass is literally widening

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the lateral plane between the anterior

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scalene muscle and the middle scalene muscle,

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and we can actually see a little bit of

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enhancement extending between the plane of

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the anterior and the middle scalene muscle.

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So, when we see that tumor that's extending

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into the plane of the anterior and the

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middle scalene muscle, then we know it

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has to be involving the brachial plexus.

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And when we see that, the most common tumor

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to arise within the brachial plexus is going

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to be a neurogenic tumor. And the most common

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neurogenic tumor is going to be a schwannoma.

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And then finally, when we look at the

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coronal images, this is that third component.

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We have to find that subclavian artery.

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So here's our subclavian artery right here.

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And remember, anytime you see that subclavian

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artery, the cords of the brachial plexus

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are going to be laying right on top of it.

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So here are the cords of the brachial plexus.

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And if we follow it medially like this,

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all of a sudden, we can see that mass

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right here involving the brachial plexus.

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And then adjacent to it, we can

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see that anterior scalene muscle.

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So literally in this case, with a leap of

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faith, we can actually see this mass involving

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the proximal portion of the divisions in

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the cords of that left brachial plexus,

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and it's arising from that C6 nerve root,

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which explains the patient's symptoms.