How to Draw the Brachial Plexus in 10 Seconds!
Probably one of the most useful resources for memorizing the brachial plexus for the upper limb exam. I drew this on the back both of my both practical and written exams, and listed the nerve fibers for each branch and the muscles innervated. Well, as many as possible. The video helped me get the foundation and visual very quickly. Learning the innervations and the paths and which fibers are found in each nerve? That’s a different story. Here is a rundown of all of the branches:
Remember To Drink Cold Beer - Roots Trunks Divisions Cords (Terminal) Branches
Branches from the Roots:
- Lateral Thoracic Nerve (C5-7) travels with Long Thoracic Artery to innervate and supply the Serratus Anterior (and breasts)—L travels with L
- Part of the phrenic nerve comes from C5 (remember this one?)
- Dorsal Scapular Nerve (C5) goes around the back (dorsal side) of the scapular to innervate the levator scapulae and rhomboids
Branches from the Trunks:
- Suprascapular Nerve (C5-6) goes through the suprascapular notch (on the superior aspect of the scapular), under the superior transverse scapular ligament to innervate the supraspinatus and infraspinatus muscles (or as I just remember, the spinatus muscles). Note about this: there is also a suprascapular artery that goes over the same ligament—you can remember “Army over Navy" in that the artery (army) goes over the ligament (a bridge), whereas the nerve (navy) travels below and under.
- Nerve to Subclavius (C5-6) is self-explanatory
Branches from Divisions - NONE
Branches from the Lateral Cord (C5-7 with the exception of lateral root of median n. (C6-7)):
- Lateral Pectoral Nerve to pectoralis major—p. major is bigger than p. minor, receives nerve fibers from two sources
- Lateral root of Median Nerve to hand and anterior forearm—median n. innervates the anterior forearm and goes through the carpal tunnel and plays a role in carpal tunnel syndrome
- Musculocutaneous Nerve provides motor to anterior arm (pierces the coracobrachialis m. before traveling between biceps brachii and brachialis mm.) and sensory to forearm (this is the cutaneous part of the name)
Branches from the Median Cord (ALL C8, T1):
- Medial Pectoral Nerve to pectoralis major and minor muscles—p. major is bigger than p. minor so it gets innervated by both lateral and medial pectoral nn while p. minor only gets innervated by medial pectoral n.
- Medial Brachial Cutaneous Nerve—Brachial = Arm, Cutaneous = Skin; ergo sensory to arm
- Medial Antebrachial Cutaneous Nerve—Antebrachial = forearm, Cutaneous = Skin; ergo, sensory to forearm
- Medial Root of Median Nerve (see above @ Lat root of Median Nerve)—C6-7 from lateral root, C8-T1 from medial root
- Ulnar Nerve—motor to portion of forearm and hand (flexor carpi ulnaris can’t be innervated by anything else…)
Branches from the Posterior Cord (C5-6 with exception of radial n. (all) and thoracodorsal n. (C6-8)):
- Upper Subscapular Nerve innervates the subscapular muscle.
- Lower Subscapular Nerve innervates the subscapular muscle and teres major muscle (minor over major—these muscles are named major and minor based on their size, but it just so happens that the minor muscle is located superior to the major muscle)
- Thoracodorsal Nerve (middle subscapular n.) innervates the back (dorsal) muscle of the trunk (thorax), the latissimus dorsi
- Axillary Nerve goes through the quadrangular space (see here) that is bordered by the humerus, what muscles inserts on the humerus? Deltoids. And then there’s also teres minor (I can’t remember how I remembered this).
- Radial Nerve, as my labmates says, is a beast of a nerve. It gives motor fibers to posterior arm and forearm and throws out cutaneous sensory nerves left and right—which is why it gets motor fibers from all roots C5 through T1.
I wish I made this post earlier (although this tumblr had yet to exist when I was studying this material), as I would’ve remembered it better. I don’t doubt that this will be helpful recalling the brachial plexus come time to study for the boards. Nevertheless, I hope this will be helpful and useful for anyone learning/reviewing/anticipating! To my fellow peers, please feel free to add anything or make corrections (I admit I’m a bit rusty with brachial plexus now!), and as always my askbox is open for questions!
Throwback! For all the first years who are learning the brachial plexus now :)
We gave our first years lunch today and they are working on this now. Good luck!