A 3-month-old infant presents with weakness in the intrinsic muscles of the hand and a 'claw hand' deformity. Sensory loss is noted along the ulnar aspect of the forearm and hand. Which of the following brachial plexus roots is primarily involved in this condition?

Explanation

Klumpke's palsy is a lower brachial plexus injury, primarily involving the C8 and T1 nerve roots. This leads to weakness of the intrinsic hand muscles and flexors of the wrist and fingers, resulting in a 'claw hand' deformity and sensory loss along the ulnar distribution. C5 and C6 involvement is characteristic of Erb's palsy.