THE BRACHIAL PLEXUS AND UPPER LIMB INNERVATION
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- เผยแพร่เมื่อ 6 ก.ย. 2024
- A plexus is a branching network of nerves or blood vessels. The brachial plexus is a network of nerves which extend from the anterior rami of cervical nerves C5-C8, as well as the first thoracic root, T1. The network passes through the cervicoaxillary canal, a passageway between the scapula and clavicle, bordered medially by the first rib. So the brachial plexus makes its way from the neck, over the first rib, into the axilla, or armpit. The brachial plexus supplies the skin and muscles of your upper limb, or upper extremity, which includes your shoulder, arm, and hand.
The brachial plexus can be divided into several sections - Roots, Trunks, Divisions, Cords, and Terminal Branches. A mnemonic for that is The Bear Came Down the River. A nerve root is the first section of a nerve leaving the central nervous system. We call these roots the C5 root to the C8 root and the T1 root. Note that although there are seven cervical vertebrae, there are 8 cervical nerves. The nerves emerge through foramina in the vertebral column.
The C5 and C6 roots join to form the upper trunk. The C7 root continues on to form the middle trunk and the C8 and T1 roots join to form the lower trunk. The scalene muscles are on either side of the brachial plexus, lateral to the cervical tract.
All three trunks split into an anterior and posterior division, with the anterior divisions being more superficial. These have different functionality - the anterior divisions supply the anterior part of the upper limb while the posterior divisions supply the posterior part of the upper limb.
The three posterior divisions fuse to form the posterior cord. The anterior divisions of the upper and middle trunks fuse to form the lateral cord. The medial cord is a continuation of the anterior division of the lower trunk. The cords surround the axillary artery and are named based on their position relative to it. The posterior cord is posterior to the axillary artery. The lateral and medial ones are on either side.
The posterior cord splits into the axillary and radial nerve. The axillary nerve passes through the quadrangular space - between teres minor and major, the long head of triceps brachii, the humerus, and the subscapularis - to innervate the deltoid and the teres minor. It also gives feeling to the shoulder joint and the skin overtop of the inferior part of the deltoid.
The radial nerve supplies the posterior upper limb, innervating the triceps, muscles in the posterior forearm, the associated joints, and the overlying skin. The lateral cord splits into the musculocutaneous nerve and the lateral root of the median nerve. The musculocutaneous nerve supplies muscles in the front of the arm - the biceps brachii, the brachialis, and the coracobrachialis muscles. It provides sensation to the lateral part of the forearm.
The median nerve proper supplies the muscles of the front of the forearm and muscles of the thenar eminence to control hand movements.
The medial cord splits into the medial root of the median nerve and the ulnar nerve. The lateral and medial root of the median nerve, the median nerve proper, and the musculocutaneous nerve and ulnar nerve on either side of it together form an “M-shape” which serves as an important anatomical reference point. The ulnar nerve innervates part of the forearm and the majority of the hand. It gives sensation to the medial forearm, medial wrist, and medial one and one-half fingers. In summary, there are five roots, three trunks, six divisions (three anterior and three posterior), three cords, and five branches.
Amazing work… May Allah gives u hidayat.
Amen
The best video I’ve seen! How does this not have more views?! 😍
I can't thank you enough for the bear came down the river :')
Been binge watching your vids for my upcoming quiz, I wish my professor taught like you! Thanks for all your work 😊
It is always hard to remember that there are 8 cervical nerves. Thanks for the visuals
Excelente conteúdo e didática . I am from Brazil , thank you!
Such a informative for me
thanks to creator of video
Thank you for sharing ❤❤❤❤❤❤❤❤
Thank you so much for giving clear insight
Thank you very much 😊
Can you explain about the anatomy of the Axilla?
Yeah!! Please
Excellent information thank you
watching this because I'm gonna have my oral exam tomorrow about the brachial plexus...
How'd it go ryuzaki
God bless you, sir 🙏🏽
thank you
Great video, helped me a lot, thank you!!!
very nicely explained bro !!!!!👍
Thank you so much ❤️
thanck u but, there is 5 nerves in posterior cord no 2 as u said : upper subscapular,lower,latissimus,axillary & radial nerves. :(
Wowww amezing ❤
Thank you!
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Thank you so much sir
thanks a lot really helpful
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Thank you ❤
Should have made a song about this 😜
I agree.
Thank youuuu
Thank you so much!!
Sooo good!
Awesome video! Tks! 👍🏽
This is great! Do you have a lumbar plexus video?
amazing
very nice
The Theacher❤️
Elaborate about radial and ulnar nerve
just started watching this gotta say its very helpful
Am a radiography student can i have a song of the hand bones please
thank you in advance
So Long To Pinky Here Comes The Thumb
Scaphoid
Lunate
Triquetral
Pisiform
Hamate
Capitate
Trapezoid
Trapezium
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Say that one more time chief
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antok nko