Identify and clean the cords of the brachial plexus and their major branches.

1. Return to the coracobrachialis muscle. Identify the musculocutaneous nerve where it enters the coracobrachialis muscles. (G 6.26;N 419;Gl 24.11C) Trace the musculocutaneous nerve distally to where its branches enter the biceps brachii and brachialis muscles. Trace the musculocutaneous nerve in the proximal direction until you reach the lateral cord. (G 6.24;N 418;Gl 24.11C)
2. Identify the lateral pectoral nerve arising from the lateral cord.
3. Trace the lateral cord in the distal direction to the point where it splits into the musculocutaneous nerve and the lateral root of the median nerve. (G 6.24;N 421;Gl 24.22) Identify and trace the median nerve distally until it passes deep to the distal tendon of the biceps brachii muscle. (G 6.35A;N 421;Gl 24.36B)
4. Follow the median nerve back in the proximal direction to the point where it arises by the union of its lateral and medial roots. Identify the medial root of the median nerve and trace this root in the superior direction to reach the medial cord. (G 6.23 and 6.25;N 418;Gl 24.34) Identify the medial pectoral nerve arising from the medial cord.
5. Trace the medial cord distally until it splits into the medial root of the median nerve and the ulnar nerve. (G 6.24;N 421;Gl 24.35) Trace the ulnar nerve distally until it passes posterior to the medial epicondyle of the humerus.
6. Return to the serratus anterior muscle. Finish cleaning this muscle. Identify the long thoracic nerve coursing along the lateral border of this muscle. (G 6.25A;N 417;Gl 24.34B) The long thoracic nerve arises from the roots of the brachial plexus. You cannot observe its origin until you dissect the neck.
7. Identify and clean the radial nerve posterior to the axillary artery at the level of the tendon of the latissimus dorsi muscle. Trace the radial nerve distally until it passes posterior to the humerus.
8. Identify and clean the axillary nerve. This nerve should be found adjacent to the posterior circumflex humeral artery at the quadrangular space. (G 6.25A;N 420;Gl 24.34B and 24.11C)
9. Trace the radial and axillary nerves proximally to the point where they arise from the posterior cord. (G 6.25A;N 418;Gl 24.34C)
10. Identify and clean the subscapularis muscle. Identify and clean the upper, thoracodorsal (middle) and lower subscapular nerves arising from the posterior cord. The thoracodorsal nerve joins the same named artery and passes to the latissimus dorsi muscle. The lower subscapular nerve often appears to branch from the axillary nerve.