What is the primary result of Duchenne-Erb palsy?

The primary result of Duchenne-Erb palsy is upper arm paralysis characterized by specific posturing, which is why this choice is the most accurate. This condition arises from an injury to the upper trunk of the brachial plexus, typically affecting the C5 and C6 nerve roots.

As a result of this injury, the affected infant may exhibit what is known as the "waiter's tip" posture, where the affected arm hangs by the side in adduction and extension, with the forearm in a pronated position. This reflects the weakness of the muscles innervated by the damaged nerve roots, particularly those responsible for shoulder abduction, flexion, and external rotation, as well as elbow flexion.

This choice correctly encompasses both the motor deficits seen in Duchenne-Erb palsy and the characteristic posture that accompanies it, helping to distinguish it from other forms of paralysis that might involve different parts of the body or present with other symptoms.