Which nerve roots are primarily associated with Erb-Duchenne palsy?

Erb-Duchenne palsy is a condition resulting from an injury to the upper trunk of the brachial plexus, which is primarily composed of the C5 and C6 nerve roots. This type of injury typically occurs during a difficult delivery when excessive lateral traction is applied to the infant's head, leading to damage in these specific nerve roots. The associated weakness is characterized by an inability to abduct the shoulder and flex the elbow, resulting in a classic arm position known as the "waiter's tip" posture.

The importance of recognizing C5 and C6 in this context lies in their role in innervating muscles responsible for shoulder abduction and elbow flexion. Damage to these roots interrupts the neural signals to the corresponding muscles, which manifests as paralysis or weakness in the affected limb. Understanding this injury helps in both diagnosis and management, highlighting the significant impact of brachial plexus injuries on motor function.