The nerves of the upper extremity are formed from a complex network of peripheral nerves that primarily originate from the brachial plexus.
The nerves of the upper extremity are formed from a complex network of peripheral nerves that primarily originate from the brachial plexus. A series of branch nerves originate from the brachial plexus proper, innervating many of the muscles of the shoulder girdle. The brachial plexus ends with 5 major branches known as the musculocutaneous, axillary, radial, median and ulnar nerves.
This post seeks to review and summarize these nerves. Illustration of the brachial plexus anatomy Illustration of the brachial plexus structure Brachial Plexus The brachial plexus is a network of nerves originating from the anterior rami of spinal nerves C5 to T1. This plexus undergoes multiple splits and mergers, ultimately giving rise to the terminal branches that provide motor and sensory innervation to the upper limb.
Additionally, it gives off several pre-terminal (supraclavicular) branches. Structurally, the brachial plexus is organized into roots, which merge to form trunks, then split into divisions, and finally reorganize into cords, from which the major nerves of the upper extremity arise. The roots merge to form three trunks of the proximal brachial plexus: the upper (C5-C6), middle (C7), and lower (C8-T1).
Each trunk then splits into anterior and posterior divisions, which regroup to form the three cords—lateral, posterior, and medial—named based on their position relative to the axillary artery. The lateral cord gives rise to the musculocutaneous nerve and part of the median nerve. The posterior cord forms the axillary and radial nerves.
The medial cord contributes to the ulnar nerve and the other half of the median nerve. Supraclavicular Branch Nerves The brachial plexus has many branch nerves that originate on the brachial plexus proper before it terminates into the cords. The dorsal scapular nerve (C5) innervates the rhomboid major, rhomboid minor, and levator scapulae.
If you are experiencing symptoms that may be related to nerve anatomy of the upper extremity, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.
*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*
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