Erb's Palsy is a condition which, due to birth trauma, may affect 1 or all of the 5 primary nerves that supply the movement and feeling to an arm. The palsy can recover fully without intervention, which mostly means surgery.

The most common cause of Erb's palsy is dystocia, an abnormal or difficult childbirth or labor. For example, it can occur if the infant's head and neck are pulled toward the side at the same time as the shoulders pass through the birth canal. The condition can also be caused by excessive pulling on the shoulders during a vertex delivery (head first) or by pressure on the raised arms during a breech delivery.

The paralysis can be partial or complete and the damage to each nerve can range from bruising to tearing. The most commonly involved root is C5 (aka Erb's point: the union of C5 & C6 roots) as this is mechanically, the furtherest point from the force of traction, therefore, the first or most affected.

The most commonly involved nerves are the suprascapular nerve, musculocutaneous nerve, and the axillary nerve. pediatric neurosurgery are often required for avulsion (tearing away) fracture repair. Lesions may heal over time and function  may return. Physical therapy is often required to regain muscle usage.

Although range of motion is recovered in many children under 1 year in age, individuals who have not yet healed after this point will rarely gain full function in their arm and may develop arthritis.