Erb's palsy is associated with injury to which region?

• A. Lower brachial plexus injury
• B. Median nerve injury
• C. Ulnar nerve injury
• D. Upper brachial plexus injury

Answer: (D)

Erb's palsy arises from injury to the upper part of the brachial plexus, specifically the C5–C6 nerve roots. Traction to the neck—such as during difficult delivery or certain traumas—damages nerves that power the shoulder and elbow (deltoid, supraspinatus, infraspinatus, biceps, etc.). Loss of these functions produces the characteristic posture: the arm is adducted and internally rotated, with the elbow extended and the forearm pronated, reflecting weakness of shoulder abduction/external rotation and elbow flexion. This contrasts with lower trunk injuries (C8–T1), which affect hand intrinsic muscles, as seen in Klumpke’s palsy. The classic region involved for Erb’s palsy is the upper brachial plexus.