While studying for the OCS exam, finding visual references can be a savior. One component of my studying has been gaining a deeper understanding of the various plexus' throughout the body. While studying I came across this animation video below discussing the brachial plexus. The brachial plexus supplies sensory and motor innervation to the shoulder, arm, forearm, and hand. Understanding the structure and anatomy of the brachial plexus makes differential diagnosis much more manageable.
Key Points from the video below:
-Brachial plexus is compiled from the spinal segments C5-T1
-The brachial plexus has roots, trunks, divisions, cords, and terminal branches (the acronym Remember To Drink Cold Beer can help remember this order.)
-The 3 trunks are the upper (C5-C6), middle (C7 alone) and lower (C8-T1).
-Each trunk has an anterior and posterior division. All anterior divisions innervate anterior compartment muscles. Posterior divisions innervate posterior muscles.
-The 3 posterior divisions form the posterior trunk (easy to remember)
-The 2 anterior divisions from the upper and middle trunks form the lateral cord.
-The 1 anterior division from the lower trunk forms the medial cord.
-Cords are named relative to the position of the axillary artery.
-The 5 terminal branches are musculocutaneous, axillary, radial, median, and ulnar nerves (The letters MARMU can help remember the branches in order.
-No smaller nerves arise directly from the divisions.
-The posterior cord gives rise to 7 nerves, one of which is the medial subscapular nerve also known as the thoracodorsal nerve.
I recommend watching this video 2-3x so you do not miss any of the clinical pearls present.
If you have any other great visual aids you use in your studies send them my way! It would be much appreciated. Enjoy.
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