Nerves and Blood Vessels of the Arm: Origin, Course, Relations, and Branches

Introduction

The arm’s neurovascular system plays a crucial role in motor and sensory functions. Understanding their anatomy is essential for diagnosing and treating common injuries, nerve entrapment syndromes, and vascular disorders.

Major Nerves of the Arm

Brachial Plexus

The brachial plexus originates from spinal nerves C5-T1 and branches into major nerves controlling the arm.

Median Nerve

• Origin: Arises from the brachial plexus (medial and lateral cords).
• Course: Travels down the medial arm and forearm.
• Relations: Passes through the carpal tunnel.
• Branches: Anterior interosseous nerve, palmar cutaneous branch.

Ulnar Nerve

• Origin: Medial cord of the brachial plexus.
• Course: Runs along the medial arm and behind the medial epicondyle.
• Relations: Enters the hand through Guyon’s canal.
• Branches: Dorsal and palmar branches.

Major Blood Vessels

Brachial Artery

• Origin: Continuation of the axillary artery.
• Course: Travels down the anterior arm.
• Relations: Lies medial to the biceps brachii muscle.
• Branches: Radial and ulnar arteries.

Clinical Relevance

Common Injuries

Fractures (e.g., humerus shaft fractures) may damage the radial nerve, causing wrist drop.

Nerve Entrapment Syndromes

Carpal tunnel syndrome results from median nerve compression.

Vascular Disorders

Thoracic outlet syndrome involves compression of the subclavian artery, affecting circulation.

Conclusion

The anatomy of the arm’s nerves and blood vessels is vital for diagnosing related pathologies.