Brachial plexus and nerves of upper limb

Published on October 31, 2022   43 min

Other Talks in the Series: Introduction to Gross Anatomy for Medicine

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I'm Dr. Banumathy, Anatomist from Tamil Nadu, India. Today, we will discuss the brachial plexus and nerves of the upper limb.
The brachial plexus is a plexus of nerves the branches from which supply the structures in the upper extremities. The brachial plexus is situated in the root of the neck, extending deep to the clavicle, and then into the axilla. The part of the plexus above the clavicle is the supraclavicular part. The part below the clavicle is the infraclavicular part.
The brachial plexus is studied in five stages. Roots stage, trunks stage, divisions stage, cords stage, and branches stage. The roots stage and the trunks stage are supraclavicular, and the cords stage and the branches stage are infraclavicular. The divisions stage is situated deep to the clavicle.
Roots stage. The roots are contributed by the anterior primary rami of C5, C6, C7, C8, and T1 spinal nerves. What is an anterior primary ramus? Each spinal nerve is attached to the spinal cord by two roots. The anterior spinal root and the posterior spinal root. The anterior root is motor in function, and the posterior root is sensory. The two roots unite to form the spinal nerve. Each spinal nerve divides into two divisions - the anterior primary ramus and the posterior primary ramus. The anterior primary ramus supplies the structures in the anterior aspect of the body. The posterior primary ramus supplies the structures in the posterior aspect of the body. The limb bud develops from the anterior aspect of the trunk. Hence, the limbs are supplied by the anterior primary rami. Hence, the anterior primary rami contribute to the roots of the plexus. Trunks stage. Three trunks are formed. Upper trunk, middle trunk, and lower trunk. Divisions stage. Each trunk divides into an anterior and a posterior division. Cords stage. The divisions unite to form three cords. Lateral, medial, and posterior cords. Branches stage. The cords give off branches at the termination at the lateral border of the pectoralis minor called terminal branches, and proximal to termination called collateral branches. Scheme of the brachial plexus.