Overview
This lecture covers the anatomical relationships and main branches of the cords of the brachial plexus in relation to the axillary artery.
Brachial Plexus Cords and Their Positions
- The cords of the brachial plexus are named based on their positions relative to the axillary artery.
- The medial cord is located medially to the axillary artery.
- The lateral cord is positioned laterally to the axillary artery.
- The posterior cord lies posterior to the axillary artery.
Terminal Branches of the Brachial Plexus
- The medial cord gives rise to the ulnar nerve.
- The medial cord also contributes to forming the medial branch of the median nerve.
- The lateral cord gives rise to the musculocutaneous nerve, which crosses the muscle for corrective activity.
- The lateral cord also provides the lateral branch for the median nerve.
- The posterior cord gives rise to the axillary nerve and the radial nerve.
Key Terms & Definitions
- Axillary artery — Major artery in the armpit region; reference point for naming brachial plexus cords.
- Medial cord — Cord of the brachial plexus found on the medial side of the axillary artery.
- Lateral cord — Cord of the brachial plexus found on the lateral side of the axillary artery.
- Posterior cord — Cord of the brachial plexus found behind the axillary artery.
- Musculocutaneous nerve — Branch from the lateral cord, innervates muscles in the anterior arm.
- Ulnar nerve — Branch from the medial cord, runs along the medial arm and forearm.
- Median nerve — Formed from medial and lateral cords; innervates most forearm flexors.
- Axillary nerve — Branch from the posterior cord, innervates the deltoid and teres minor muscles.
- Radial nerve — Branch from the posterior cord, innervates muscles of the posterior arm and forearm.
Action Items / Next Steps
- Review anatomical diagrams of the brachial plexus and its relation to the axillary artery.
- Memorize the major branches that arise from each cord.