brachial plexus?

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nev

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So we are going over the brachial plexus this week in gross. Stuff looks pretty complex, do you guys know of any mnemonics or learning tools which will make it easier to learn and stick?
Thanks
Nev
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The website above seems pretty helpful. Just like anything else though, it seems daunting at first but just draw it on a huge whiteboard about 15 times and its not so bad. Drawing it both left and right helps.

Real Texans Drink Cold Beer or Randy Travis Drinks Coffee Black are mnemonics for the roots/trunks/divisions/chords/branches.

The hard part is remembering how the branches and the cutaneous nerves course through the compartments of the arms.
 
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Its not as bad as it looks at first. Just try drawing it out on your own. Fill in what you missed and draw it again. And again. After a few times drawing it out you'll have it down, and be able to picture it in your head.

Then when you're in the lab, just look in order. Look for all the landmarks and try to see what is where in relation to everything else. I found Rohen's helpful, although their brachial plexus was absolutely perfect and looked like it was right out of netters, while my cadaver was far from perfect. Look for the M.
 
I don't recommend mnemonics unless it's a last resort. If you're just starting you will be helping yourself if you try to truly understand it and make sense of it. Almost all anatomy has an underlying logic to it, and if it doesn't then it can usually be explained embryologically....that said, the posterior cord gives off branches to muscles in the posterior back, they share common sites of origin and insertion, and therefore actions, etc etc. Kinda just have to learn it.
 
My -Musculocutaneous n.
Aunt - Axillary n.
Rapes - Radial n.
My - Median n.
Uncle - Ulnar n.
 
dude you just gotta go to anatomy lab on your own and look at MANY cadavers. Variation is key because there are more than 10+ variations of the brachial plexus in the populations. I notice differences in many of the cadavers and when it comes down to the pinning its not gonna look as pretty as those headless arrow diagrams. I learned that diagram too but it never helped. You just gotta get in the grind son.
 
"3 Musketeers Assassinated 5 Rats, 5 Mice, and 2 Unicorns."


Recite this while linking them with your fingers that represent the spinal nerves.

C5 = Thumb
C6 = Index Finger
C7 = Middle Finger
C8 = Ring Finger
T1 = Pinky


"3 Musketeers..."

[Extend your thumb, index, and middle fingers, representing C5, C6, and C7 of Musculocutaneous.]

"...Assassinated..."

[Extend your thumb and index fingers, pointing a gun, representing C5 and C6 of Axiallary.]

"...5 Rats, 5 Mice,..."

[All 5 Spinal Nerves. Rats and Mice? Just because they're related. Radial and Median.]

"...and 2 Unicorns."

[No idea why it's 2 Unicorns. This is just the one you have to remember and that Ulnar is your ring and pinky fingers.]


During exams, you can see people doing this thing with their hand, silently.

👍
 
Last edited:
Marcus Brody said:
... Almost all anatomy has an underlying logic to it, and if it doesn't then it can usually be explained embryologically....
Click to expand...

So true...the other day i was going over my netter flashcard. Then, I saw a superficial muscle on the anterior compartment of the leg (Tibia side) that is inserted in cuneiform...Without hesitation, my first guest was ANTERIOR TIBIALIS...Guess what? that was the right answer.

That is why I am now realized that you only need to study the basics when it comes anatomy, the rest comes with common sense!
 
I use "ULTRA" for everything coming off the posterior cord and "Many Medical Men Use Morphine" for the medial cord.
Honestly though, mnemonics are not that helpful for the brachial plexus. Get some tracing paper and trace it a few times; then draw it over and over from memory. You just kind of absorb it as you re-draw it. It looks very different in the body though. As someone mentioned above, get your M in place, and you'll be fine.
 
When trying to identify one of the nerves on the cadaver, the easiest thing is to just look and see what muscles its going to. I have a really hard time just identifying a nerve based on its location within the brachial plexus itself.
 
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I'll post my brachial plexus notes to my Blog. Should clear some things up and help you visualize things. If the download doesn't show up immediately, just check back in a day.

BRACHIAL PLEXUS
 
I really don't think the brachial plexus is that hard once you look at a few times and think about it in relation to your body. I have more trouble identifying it on bodies than remembering the diagram.

The hardest things to me so far are the things not listed on the BP diagram. I.e. cutaneous branches and where they come from, muscles supplied by the anterior interosseus branch of the median nerve or similar such as the deep branch of the ulnar nerve. What would be the difference in muscle function if you have a lesion of the median nerve at the wrist as opposed to one in the arm? Stuff like that.
 
The brachial plexus is ridiculously easy. You'll look back on it in a few weeks and see what I mean.

1. DO NOT draw it first. Learn what nerves innervate what muscle. The good thing about this is that the upper and lower limbs have compartmental innervation, which makes this task super easy as well. Radial: posterior arm and forearm (all extensors). Musculocutaneous: Anterior arm. Median: anterior forearm (with exception) and some of the hand. Etc, etc.

2. Learn the terminal branches of these. For example: deep branch of ulnar nerve, recurrent branch of median nerve, deep branch of radial nerve and superficial branch of radial nerve, etc.

3. Once you have the innervation down on paper, then attempt to draw it. If you try to draw the plexus before you actually learn what it DOES, you are just memorizing lines traveling across a piece of paper. You don't really understand what you're drawing. After you understand the plexus in the body, then you should draw it on paper. This will help you translate your knowledge instead of simply memorizing the paths of different lines.

4. I personally think you should attempt to draw the plexus in the most fluid and organic manner possible. The roots, trunks, divisions, cords and branches aren't all straight lines in the body. They are fluid, organic structures that move around. I came up with my very own drawing of the plexus based on this, and it helped me form a better picture in my head when I was looking at cadavers.

5. Biggest point of all: don't get overwhelmed. The brachial plexus is a very simple structure and very straightforward once you have spent some time with it. You'll see how easy it is once you see the lumbosacral plexus. And then when you master that, you'll think the brachial plexus was kindergarten material.
 
Thanks a lot for the info, guys!
 
look @ quickys link (2nd post down) .. it simplifies the drawing of the brachial plexus so i was just wondering if there is something like that for other plexus's
 
I feel like I'm the only one in my class who doesn't get this and that I'll be laughed at if I ask.

I went to this site and I know how to draw out the brachial plexus. I get where everything goes and all that. But can someone please tell me how to apply it? What does it all mean? I'm behind in Anatomy and I'm trying to keep up with the lectures and people are applying the brachial plexus all over the place for figuring out nerve roots and all I see is a bunch of lines and arrows going every which way and don't understand the paths that I'm supposed to take.

Can someone explain it in simple terms and walk me through one?

http://www.ama-assn.org/ama1/pub/upload/mm/15/brachial_plex_how_to.pdf
 
MedStudentWanna said:
I feel like I'm the only one in my class who doesn't get this and that I'll be laughed at if I ask.

I went to this site and I know how to draw out the brachial plexus. I get where everything goes and all that. But can someone please tell me how to apply it? What does it all mean? I'm behind in Anatomy and I'm trying to keep up with the lectures and people are applying the brachial plexus all over the place for figuring out nerve roots and all I see is a bunch of lines and arrows going every which way and don't understand the paths that I'm supposed to take.

Can someone explain it in simple terms and walk me through one?

http://www.ama-assn.org/ama1/pub/upload/mm/15/brachial_plex_how_to.pdf
Click to expand...

No one can "walk you through" a diagram on an online forum. Why don't you discuss it with one of your classmates?

What do you mean by "how to apply it"?

Here's one application:
Guy comes in with anterior shoulder dislocation, he has paresthesia over lateral upper arm, which nerve is impinged?
 
Holy crap, that is brutal. I much, much, much prefer the more anatomic-looking drawings to those awkward stick figure mock-ups, but if you must use one, First Aid has a pretty darn good rendition with the nerve palsies on the next page for easy reference. HY Anatomy also has some useful tables and drawings.
 
nima123 said:
No one can "walk you through" a diagram on an online forum. Why don't you discuss it with one of your classmates?

What do you mean by "how to apply it"?

Here's one application:
Guy comes in with anterior shoulder dislocation, he has paresthesia over lateral upper arm, which nerve is impinged?
Click to expand...

I don't know, axillary? That's what I mean. I don't know how to get the answer from the drawing. We just started Anatomy this week so maybe it'll come to me after a few more weeks in lab/lecture, but right now, I'm so lost.
 
I replied to a thread last week, I believe, that was titled "brachial plexus". The OP basically had the exact same problem. Take a look at that thread read quick.

But for now..

I think your problem is that you probably don't understand the brachial plexus in general. A plexus is basically a point in your body where axons from various nerve roots come together, intermingle, and then redeploy to their final destinations. This is the basic gist of the brachial plexus, or any plexus for that matter (lumbosacral and cervical, which you will get to soon enough). What this basically means is that a specific nerve (take the median for example) can receive axons from various levels of the spinal cord (via the various "roots" which combine) and then go on to innervate whatever it is that it innervates (for the median this is the flexors on the forearm). This concept is important because a nerve lesion at a specific point on the plexus may only give you partial sensory or motor loss, and not complete, because of the fact that the axons in a particular nerve come form a variety of spinal cord levels.

You need to begin by understanding the innervation of the muscles of the brachium (arm) and antebrachium (forearm). Once you understand that, you can begin to work your way up the arm towards the plexus itself. You will not learn the plexus simply by drawing it, because as you have seen, it is just a bunch of lines running across a page. You can't apply it because you don't understand it.

You also need to come up with your own drawing of the plexus. This will help you because it stems from your own understanding. This will help further solidify the understanding in your head and will make application of the plexus much easier come test time.
 
MedStudentWanna said:
I don't know, axillary? That's what I mean. I don't know how to get the answer from the drawing. We just started Anatomy this week so maybe it'll come to me after a few more weeks in lab/lecture, but right now, I'm so lost.
Click to expand...

If your anatomy exam questions are all clinical like mine are, buy BRS. It is amazing. The questions are difficult but the answers are provided with great explanations. It especially helped with upper limb. Do these practice problems over and over, you'll there are definitely some things that are asked all the time. i.e. Damage to what nerve causes "winged scapula"; so-and-so has carpal tunnel and her median nerve in impinged, movement of which finger will be impaired the most... etc.
 
MrBeauregard said:
I replied to a thread last week, I believe, that was titled "brachial plexus". The OP basically had the exact same problem. Take a look at that thread read quick.

But for now..

I think your problem is that you probably don't understand the brachial plexus in general. A plexus is basically a point in your body where axons from various nerve roots come together, intermingle, and then redeploy to their final destinations. This is the basic gist of the brachial plexus, or any plexus for that matter (lumbosacral and cervical, which you will get to soon enough). What this basically means is that a specific nerve (take the median for example) can receive axons from various levels of the spinal cord (via the various "roots" which combine) and then go on to innervate whatever it is that it innervates (for the median this is the flexors on the forearm). This concept is important because a nerve lesion at a specific point on the plexus may only give you partial sensory or motor loss, and not complete, because of the fact that the axons in a particular nerve come form a variety of spinal cord levels.

You need to begin by understanding the innervation of the muscles of the brachium (arm) and antebrachium (forearm). Once you understand that, you can begin to work your way up the arm towards the plexus itself. You will not learn the plexus simply by drawing it, because as you have seen, it is just a bunch of lines running across a page. You can't apply it because you don't understand it.

You also need to come up with your own drawing of the plexus. This will help you because it stems from your own understanding. This will help further solidify the understanding in your head and will make application of the plexus much easier come test time.
Click to expand...

👍
 
I hate that stick drawing as well. I just used the picture in Netter's, because at least you can follow what divisions are anterior and posterior and whatnot.

If you have damage to C5 at the root, the muscles losing function will be different from those losing function at the posterior cord, which has components of C5, but of other roots as well.

General example, traced from the muscle to the root:

Brachialis is innervated by the musculocutaneous nerve.
The musculocutaneous nerve is a terminal branch of the lateral cord.
The lateral cord arises from a junction of the anterior divisions of the superior and middle trunks.
The superior trunk is composed of C5 and C6 roots (ventral rami). The middle trunk is from C7.

Thus, with a loss of function in the brachialis you'd suspect injury to the musculocutaneous nerve, or the lateral cord, or the superior or middle trunks or C5, C6, or C7. Further tests of course would be required to narrow it down - for example you'd want to see if only the brachialis, biceps, and coracobrachialis were out and the rest of the arm was fine, or if some of your forearm flexors were affected, which would indicate damage higher up the plexus.

The actions of the muscles innervated by these roots appear to follow certain patterns as well. One of the surgeons helping out in lab had this nice song and dance showing movements while reciting the following list... can't really replicate that online, but you can figure it out. I mean, some things flex the forearm versus the hand, so you can make up your own little dance to do while you sing the names of the roots. She did it without stating the nerves, but without the dance it doesn't make sense, so I included the nerve names:

Axillary - C5, C6
Musculocutaneous - C5, C6, C7
Radial - C5, C6, C7, C8
Median - C7, C8, T1
Ulnar - C8, T1

Have fun with that. 😀
 
Helps determine the site/cause of neuropathies from the constellations of signs and symptoms you see on exam. So, patient has weakening in certain muscles, total paralysis of others, normal function of others, and it doesn't make much sense unless you know the common innervations of these muscles as well as the ones that remain functional. Then you can logically deduce a common cause or set of causes, and maybe even location where the nerve problem is. Based on that knowledge you can decide the likelihood of more serious underlying issues going on- cancer, autoimmune dz, etc- or the potential benefits/consequences/risks of treatment or lack thereof.
 
Thanks everyone who replied. I think I have to conceptually understand the brachial plexus first and then revisit this thread.
 
MedStudentWanna said:
Thanks everyone who replied. I think I have to conceptually understand the brachial plexus first and then revisit this thread.
Click to expand...

You'll be seeing the nerves and what they innervate in lab. When you see that, it will bring the relevant questions to your mind and you'll understand what that stick figure is getting at. It's just a model to help you quickly understand where everything's coming from rather than trying to memorize every minute detail without integrating it into a functional setting.
 
While studying for my first anatomy exam I did something stupid. I busted out my netters flash cards and just started doing them over and over. I got totally and utterly overwhelmed.

You need to listen to lectures and just take stuff in little by little. Dont try to skip ahead. Your professors know what theyre doing and paint the picture little by little for you. A lot of anatomy is rote memorization...but you can save yourself a lot of time by just understanding concepts. Remember the exceptions to the rule...rather than the things that abide by the rule.

Like all the anterior muscles of the arm are innervated by the median nerve......except flexor carpi ulnaris, flexor pollucis longus, and pronator quadratus.....stuff like that.

Ectoderm makes the CNS and skin
Endoderm makes the gut and associated organs
Mesoderm makes everything else.

Understand?
 
willen101383 said:
Like all the anterior muscles of the forearm are innervated by the median nerve......except flexor carpi ulnaris, flexor pollucis longus, and pronator quadratus.....stuff like that.
Click to expand...

Fixed. (Also ulnar part of flexor digitorum profundus)

What helped me was making sure I understood the innervation of the muscles as well as where the nerves travel. After that the questions in BRS were much easier.
 
1) Check out this brachial plexus animation:

http://anatomyuniverse.com/UE_BPlexus_Animation.html

and diagram:

http://anatomyuniverse.com/UE_BPlexus.html

Try to memorize the overall scheme.

2) Then spend some time clicking on those diagrams (they have popup panels with extra information about muscle innervation, action and blood supply):

http://anatomyuniverse.com/UpperLimb.html

(also:
http://anatomyuniverse.com/AxillaryArtery.html
http://anatomyuniverse.com/UpperLimbSpaces.html)

When you do this, try to integrate with the information from the
first diagram.

3) Lastly, think of it clinically. For instance: "if a guy can't lift his arm, what cord might be affected (smth like this) and what nerve roots are involved?" Go back to the diagrams and animations to answer it.

4) Practice, practice, practice.

Good luck!!!!
 
There's a page in Netters that has it drawn out. Just draw it over and over until it sticks. It'll maybe take like half an hour. I also remember the nomenclature seeming to resemble a tree ...like roots, trunk, branches, etc, from proximal to distal.
 
Our exams had double-whammy questions, like a muscle in the arm would be pinned and they'd ask what branch/trunk/whatever provided the innervation. Or tripple-whammy: what trunk innervates the antagonist of that muscle. Booooo.
 
Zoom-Zoom said:
There's a page in Netters that has it drawn out. Just draw it over and over until it sticks. It'll maybe take like half an hour. I also remember the nomenclature seeming to resemble a tree ...like roots, trunk, branches, etc, from proximal to distal.
Click to expand...

Seriously. Fck these memory aids. Just learn it, people.
 
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