The Brachial plexus mnemonics is a unique cheat-code to learning the nerves of the upper limb.
Once you grab your heads hooked into them, forgetting the nerves or any concept relating to brachial plexus nerves, will almost be impossible!
Have you been searching for an easier way to remember all the cords, roots, branches and injuries of the brachial plexus?
Then, you my friend, have landed in the perfect domain!
Here’s what we are going to do in this mnemonic series. First of all, we’re going to show you how to remember the parts of the brachial plexus easily.
I’d also show you how to remember the arrangements, cords and all the branches. You’d also get our mnemonic for all the nerves and their corresponding roots!
And that’s not all; you’d also learn the mnemonic to remember the brachial plexus injuries and their causes!
I have stragized all this information in this brachial plexus mnemonic so that you’ll be able to ace any related test that arrives your way.
If you’re ready to jump in on this learning experience, then grab a seat, and let’s get started right away!
Definition of Brachial Plexus
If you want to learn the brachial plexus, it’s good to first understand the underlying concepts behind everything.
To spare you an academic definition, here’s what brachial plexus simply means;
It’s coined from the two words “brachial” and “plexus” where the former means arm and the later means network.
So, brachial plexus can be defined as the network of nerves that supplies the upper limb with both motor and sensory innervation. Get the gist?
From the above context, sensory innervation means the nerves which transmits sensations from the skin of the upper limb to the central nervous system while the Motor innervation describes the nerves that carry impulses from the CNS to the muscles to cause a response.
The brachial plexus is formed from the anterior/ventral rami of the Lower four cranial nerves and the first thoracic nerve.
Remember that there are 8 cervical nerves even though they’re 7 cervical vertebra. In summary, brachial plexus is formed from C5, C6, C7, C8, and T1.
Mnemonic for the Components of the Brachial plexus
The components of the brachial plexus in sequence are:
Learning this for the first time, and remembering the order in which they occur might be challenging.
But with these mnemonics, remembering the components of the brachial plexus will be a breeze!
Here are the brachial plexus mnemonics below:
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Where R: Roots, T: Trunk, D: Division, C: Cords, B: Branches.
Location of the different components of the brachial plexus
Learning where each part of the brachial plexus is located is very important. Here’s a list of the parts with their location and also a good mnemonic for remembering them;
- Roots: Between the anterior and medial scalene muscles
- Trunks: Posterior triangle
- Divisions: Behind the clavicle
- Cords: round the second part of the axillary artery in the Axilla
Also note that; the cords of the brachial plexus is the only part that’s located in the Axilla. Remember this, as it’s a popular exam question!
So, here’s the mnemonic for remembering the locations of the different parts of the brachial plexus:
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Where S: Scalene muscles, P: Posterior triangle of the neck, C: Clavicle, and A: Axillary artery.
How is the Brachial Plexus formed?
The network of nerves in the upper limb contain 17 branches that give supplies to different structures in the area. But how are the 17 branches formed? Where do they arrive from? Let’s look at it below;
After the five roots have descended from the vertebral foramina between the anterior and medial scalene muscles, the anterior rami proceed to form 3 trunks in this order below:
- The C5 and C6 combine to form the Upper trunk
- C7 continues as the middle trunk
- C8 and T1 combined to form the lower trunk
So in summary, there are 3 of them; upper, middle and lower trunks.
The 3 trunks then proceed to split into two each: an anterior and posterior division. That is, the upper trunk forms anterior and posterior divisions, middle and lower trunk do the same, making it 6 divisions.
So you should be able to answer this; How many divisions are in the brachial plexus? 6!
The formation of the cords of the brachial plexus is one part that the majority of students find tricky.
Although, you may not get it at first read, you should understand this and commit to your memory.
The anterior division of the upper and middle trunk combines to form the Lateral cord.
The posterior divisions of all the cords unite to form the posterior cord of the brachial plexus mnemonic.
The posterior division of the lower trunk then continues as the medial cord.
Branches for the brachial plexus and mnemonics
Here the main deal on the brachial plexus mnemonic. There are 17 branches of this network and you’re expected to know all of them plus their nerve root.
I can hear you exclaiming already, but there’s no need to worry. With these brachial plexus mnemonics I’ll outline below, learning and remembering everything will be a breeze!
Branches from Brachial Plexus roots and Mnemonics
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Where D is Dorsal scapular nerve, and L: Long thoracic nerve. Both arrive from the roots.
N is Nerve to subclavius and S: Suprascapular nerve. Both come from the trunks.
- Dorsal scapular nerve has nerve root: C5 while,
- Long thoracic nerve has nerve root C5, C6, C7.
But concerning the roots from the trunks, all of them have nerve roots C5, C6. So;
- Nerve to subclavius: C5, C6
- Suprascapular: C5, C6
|Nerve||muscle it supplies|
|Dorsal scapular||Levator scapulae, Rhomboid major and Minor|
|long thoracic nerve||Serratus anterior|
|Suprascapular nerve||Supraspinatus and Infraspinatus|
|Nerve to subclavius||Subclavius muscle|
Branches from the lateral cord and mnemonics
The nerves that come from the Lateral cord of the brachial plexus is ML^2. That is M•L•L. Where ;
- M: Musculocutaneous nerve
- L: Lateral pectoral nerve
- L: Lateral root of the median nerve
|Nerve||Muscles it supplies|
|Lateral pectoral nerve||Pectoralis major|
|Lateral nerve of median nerve||Combines with the medial root to become the median nerve|
Note: BBC Muscles refers to the three anterior muscles in the forearm I.e the Biceps brachii, Brachialis and Coracobrachialis.
Code: All branches from this root are supplied by the C5, C6, C7.
Branches from the medial cord of brachial plexus mnemonics
There are five branches from this medial cord and you can remember them easily using the mnemonic: M4U. That is there are four M’s and one U. Here’s what they all entail;
- Medial root of the median nerve
- Medial cutaneous nerve of arm
- Medial cutaneous nerve of forearm
- Medial pectoral nerve
- Ulnar nerve
Code: The four M’s have nerve root C8, T1 while the ulnar nerve has C5, C6, C7.
Also note that the medial root of the median nerve as root C8, T1 but it’s only when it has united with the lateral root of the median nerve to become the median nerve that it is C5, C6, C7, C8, T1.
|Nerve||Muscle It Supplies|
|unites with the lateral root to become the median nerve|
|Medial cutaneous nerve of the arm||gives sensory innervation to the medial side of the arm|
|Medial cutaneous nerve of the forearm||gives sensory innervation to the medial side of the forearm|
|Medial pectoral nerve||Pectoralis major and minor|
|Ulnar nerve||skin over the palmar surface of the little finger, medial half of ring finger, and associated Palm and wrist|
Notes: the medial cutaneous nerve of the arm is the smallest branch of the brachial plexus.
Branches from the posterior cord of the brachial Plexus and mnemonics
The posterior cord also has five branches, and a good mnemonic you can use to remember them is ALUTRA. Where;
- A: Axillary nerve
- L: Lower subscapular nerve
- U: Upper subscapular nerve
- T: Thoracodorsal nerve
- Ra: Radial nerve
From the beginning to the end, use this code to remember their nerve roots;
ALU has C5, C6, C7. T has C8, T1 while Ra: has all of them, I.e C5, C6, C7, C8, T1. Get all the gist?
|Nerve||Muscle It Innervates|
|Axillary nerve||Deltoid and Teres minor|
|Lower subscapular nerve||Lower part of subscapularis and teres major|
|Upper subscapular nerve||Upper part of subscapularis|
|Thoracodorsal nerve||Lattisimus Dorsi|
Injuries of the Brachial plexus Mnemonic
There are six conditions that are known to be caused by the injuries to the brachial plexus. And again, learning them will be breeze with these mnemonics below:
Winging of scapula
The Serratus anterior which is supplied by the long thoracic nerve is responsible for protracting the scapula. But when the nerve is injured, problem arrives, and one would lose the ability to protract hence leading to a winged scapula (winged because it bulges outside like the wing of an angel, or maybe a bird🙂).
Have you ever heard the phrase “take your problems by the horn”? There’s a concept there that I connect with this syndrome. I guess it may also help this stick.
What is horners syndrome? It results when there’s damage to all the roots (all the problems) of the brachial plexus. Get the gist?
Erb’s Paralysis/ Duchenne’s Paralysis
This is an injury to a region of the upper trunk of brachial plexus called the Erbs point ( six nerves unite here). It can be caused by birth injury, fall in the shoulder, anesthesia, breech delivery, etc.
This syndrome arrives from injury to the Lowe trunk and it’s caused by hyperabduction of the arm which may occur as a result of a fall on an outstretched arm. It can also be caused by extended arm in breech delivery.
Saturday’s night palsy
This complication is caused by the compression of the radial nerve when a drunkard gets into a deep sleep with arm hanging Over the back of a chair.
In all, you can remember all the brachial plexus injuries using the mnemonic: WHECKS
- W- Winging of scapula
- H- Horner’s syndrome
- E- Erb’s paralysis
- C- Crutch palsy
- K- klumpke’s paralysis
- S- Saturday night palsy
So there you go, all the brachial plexus mnemonics to recall all the concepts with ease!
If there’s anything you need clarification on? Then let me know using the comment box below! Other than that, do share this content with your friends and colleagues.
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