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My name is Suresh Mukherjee and I'm a clinical

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professor of radiology at the University

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of Illinois at Radiation Oncology at the

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Robert Wood Johnson School of Medicine.

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I'm also a faculty member of otolaryngology head and

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neck surgery at Michigan State University.

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I also serve as national director for head

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and neck radiology at ProScan Imaging.

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This talk will be on the brachial plexus.

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The brachial plexus is something that we covered

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in medical school for a fair amount of time, but

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unfortunately, many of us forgot that anatomy.

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And it can be complex, but if you are

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a radiologist, eventually you will

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have to deal with the brachial plexus,

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whether you're a neuroradiologist looking

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down at the base of the neck, or whether

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you're a musculoskeletal radiologist.

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Because the shoulders are

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innervated by the brachial plexus.

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And even chest radiologists, because oftentimes

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you'll have pathology extending into the lung

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apices that can involve the brachial plexus.

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So therefore, you really can't escape it.

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So what we're going to do is discuss the

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classical anatomy of the brachial plexus.

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And then we'll show you how you can

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look at this on your imaging studies.

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So the classical anatomy of the brachial

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plexus that we learned in medical

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school is that it's divided into the

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roots, the trunks, the divisions, and cords.

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And sometimes, this type of

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anatomy is hard to remember.

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So, for me, I always like mnemonics.

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So, if I can always remember that

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radiology techs drink cold beer, and you

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can change beer to beverages if you like,

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but if you could remember the radiology

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techs drink cold beer, you could say,

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you'll always be able to understand

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the components of the brachial plexus.

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So when we break down the brachial

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plexus, the brachial plexus is supplied

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by C5 through the T1 nerve roots.

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And the C5 and the C6 roots

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combine to form the upper trunk.

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The C7 nerve root is by itself

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and forms the middle trunk.

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And then C8 and T1 combine

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to form the lower trunk.

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So in this schematic illustration, here's

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C5 and C6, and it forms the upper trunk.

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This is C7, which forms the middle trunk.

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And then you have C8 and

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T1 forming the lower trunk.

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Then eventually what happens is

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that these trunks end up dividing.

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So these trunks end up dividing and

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then the divisions eventually go on to

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form the cords of the brachial plexus.

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So the cords of the brachial plexus

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are named based on their relationship

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with the axillary or subclavian artery.

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So this red rectangle is here to identify and

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illustrate the axillary/subclavian vein.

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You have one cord

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that's posterior to the vein.

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You have another cord

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that's lateral to the vein.

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And then you have another cord

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that's medial to the vein.

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So again, the cords are named in relationship

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to the axillary/subclavian artery.

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So that's the classical anatomy of the brachial

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plexus that we learned about in medical school.

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So again, just to reiterate,

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C5, C6, C7, C8, and T1.

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We talked about the trunks,

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then we talked about the divisions,

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and then we talked about the cords.

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Now, the surgeons have their own definition

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of the brachial plexus, and that's based

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on the relationship to the clavicle.

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So on this schematic illustration, we can see

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the clavicle here, and the surgeons look at

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the brachial plexus as a component that's above

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the level of the clavicle, then you have a

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component that's behind the clavicle, and then

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you have a component that's below the clavicle.

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So this is the supraclavicular plexus,

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which is comprised of the roots,

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some of the nerves, and the trunks.

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The retroclavicular portion of the brachial

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plexus includes the divisions, and then the

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infraclavicular portion is predominantly

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comprised of the cords and the distal nerves.

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So you can see how the surgical anatomy

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has to take into account the standard

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anatomy that we learned back in medical

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school, the classical anatomy, if you will.

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So to put it all together, the

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third type of anatomy that I refer

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to is the radiological anatomy.

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And the radiological anatomy is as follows:

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In order to really understand the

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brachial plexus, there are three main

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components and three main anatomical

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areas that you have to be aware of.

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And if you can remember these three

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main anatomical areas, the brachial plexus

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actually will literally jump out at you

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on any type of study that you look at.

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So, the supraclavicular plexus that we

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talked about, and that's a nomenclature

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that the surgeons use, is comprised of the

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anterior and the middle scalene muscles.

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So, if you look at this schematic illustration,

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this is the anterior scalene muscle, this is the

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middle scalene muscle, and between these muscles

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comprises the supraclavicular brachial plexus.

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So, when we look at this anatomic image on the

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left, there's a lot of stuff going on right

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here, because we can see the thyroid

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gland, we can see the trachea, we can see the

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esophagus, we can see the vertebral body, we

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can see the paraspinal muscles, we can see

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arteries and veins, so it's relatively complex.

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But what I want you to be able to do is

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identify this muscle right here, which

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is the anterior scalene, and this muscle

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posterior to this with the middle scalene,

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and then if you look between the plane of

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the anterior and the middle scalene muscles,

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there's the brachial plexus.

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If you look at the opposite side,

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there's the anterior scalene, there's

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the middle scalene, and there's the

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brachial plexus right between them.

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So when you look at the brachial plexus,

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there's a lot going on, but these

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muscles, the anterior and middle scalene

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are pretty big muscles, and if you can find

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those, the brachial plexus is located within them.

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On the right-hand side is

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an axial T1-weighted image.

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And right here, we can see

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the anterior scalene muscle.

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There's the middle scalene muscle

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and there's the brachial plexus.

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Notice how it jumps right out at you.

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That's the supraclavicular

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component of the brachial plexus.

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On the patient's left-hand side, there's

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the anterior scalene, there's the middle

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scalene, and right between these are

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the supraclavicular brachial plexus.

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Now, this image on the right-hand side is

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really taken from a cervical spine MRI.

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And depending on how you do your cervical

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spine MRIs, whether or not you use a pre

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saturation pulse, if you don't use it, what

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I would encourage you to do is, yes, go

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ahead and look at all the pathology that's

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involved in the cervical spine, but over

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the next 20 cases, literally just look at

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the anterior and middle scalene muscles,

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and you'll see that brachial plexus.

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And once you do that, that supraclavicular

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portion of the brachial plexus will

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be very, very easy for you to see.

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That second component of the brachial

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plexus is comprised of the retro-

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and the infraclavicular plexus.

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And we can always find this by looking

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for the third main piece of anatomy,

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that we have to be familiar with:

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And that's the axillary

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slash subclavian artery.

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So, when we look at the anterior scalene muscle

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here, this artery that's medial to the anterior

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scalene muscle is the subclavian artery, and

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as it extends laterally to the anterior scalene

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muscle, it changes names to the axillary artery.

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And we can see on this schematic illustration

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that the cords of the brachial plexus are

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directly adjacent to the subclavian artery.

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In fact, when we talked about how these

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cords are named, they're specifically named

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based on the relationship to this artery, and

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once it gets lateral to the anterior scalene

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muscle, it's called the axillary artery.

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So when we look at the coronal images

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on this anatomic section, the arrow is

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pointing right here at the subclavian

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artery, and then just above it, we can

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see the cords of the brachial plexus.

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Similarly, on the left-hand side,

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here's that subclavian artery.

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As it extends laterally, it changes

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the name to the axillary artery.

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And right above it, we can see

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the cords of the brachial plexus.

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Laying right on top of it on the right-hand

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side is a fat-suppressed T2-weighted image. The

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arrow points at the subclavian artery, and right

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above it, lo and behold, we can see the cords

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of the brachial plexus. In fact, it looks just

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like spaghetti or some type of linguine

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that is literally laying on the subclavian

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artery on the left-hand side. Again, there's

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that subclavian artery, and right above it are

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the cords of the brachial plexus. So we can

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use this now to look at the brachial plexus

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on the sagittal images. The sagittal images

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were the way I initially learned to look at the

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brachial plexus, and quite frankly, I thought

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it was a little bit confusing, so I always

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default to the axial and the coronal images.

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But if you do look at the sagittal images,

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this is the anterior scalene muscle here.

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Here is the subclavian artery located

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just posteriorly to the anterior scalene

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muscle, and just adjacent to this

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are the cords of the brachial plexus.

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So, in summary, what we covered was

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the anatomy of the brachial plexus

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and how to find the brachial plexus.

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So as we begin this mastery course, it's

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important to understand that what you

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always have to look for are the anterior

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scalene muscle and the middle scalene muscle,

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because this identifies the supraclavicular

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portion of the brachial plexus.

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The third component is the subclavian artery.

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The subclavian artery is a big structure,

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and once you find that subclavian

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artery, you'll always be able to find

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the cords of the brachial plexus.

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And then, as the mastery course progresses,

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we're going to talk about a variety

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of entities that can cause brachial

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plexopathies, which include things like

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trauma, neoplasms, and inflammatory processes.

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And as we do this, we'll always revert back to

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the anatomic localizer, the brachial plexus.

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And hopefully, by the end of this course,

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you'll learn to love the brachial plexus.