A 25-year-old diver sustains cervical cord injury at C5. He has complete motor and sensory loss below C5 bilaterally. ASIA classification is A. He retains elbow flexion but cannot extend the wrist. Which muscle is expected to function and how can it be used for tendon transfer?

• A Deltoid (C5) can be transferred to biceps to restore elbow flexion
• B Brachioradialis (C5-C6) is functional — can be transferred to extensor carpi radialis brevis (ECRB) to restore wrist extension ✓
• C Pronator teres (C6) is functional — transfer to flexor digitorum profundus for grip
• D No useful muscles exist below C4 for transfer in C5 ASIA A injury

Explanation

In C5 ASIA A complete cord injury, muscles innervated at C5 (deltoid, biceps, brachialis) and partially C6 may be functional. Brachioradialis is innervated by C5-C6 (radial nerve) and is typically preserved or partially preserved at this level. The Moberg procedure and modifications use brachioradialis transfer to extensor carpi radialis brevis (ECRB) to restore active wrist extension, which is fundamental for the tenodesis grasp mechanism (passive finger flexion when wrist extends). This reconstruction is the cornerstone of upper limb function restoration in C5-C6 tetraplegia.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.