Which therapeutic activity is MOST appropriate for an infant with a C5-C6 brachial plexus injury?

• A. Open-hand batting of an object with finger extension and abduction
• B. Reaching with shoulder medial (internal) rotation and forearm pronation
• C. Reaching with shoulder lateral (external) rotation and forearm supination
• D. Grasping an object with thumb (1st digit) adduction and metacarpophalangeal joint flexion

Answer: (C)

When a baby has a C5-C6 brachial plexus injury, the movement pattern to restore is shoulder external rotation with forearm supination, because weakness there causes the arm to rest in internal rotation and pronation. Encouraging reaching with the shoulder in external rotation and the forearm in supination directly promotes the needed alignment and control to bring the hand toward use and prepares for grasp. The other options either emphasize internal rotation and pronation, or focus on finger-level actions without addressing the proximal shoulder/arm mechanics, which are the primary challenge in this injury.