From this review, the following points have emerged: 1. The typical obstetrical palsy is a traumatic lesion caused by forced lowering of the shoulder during delivery. 2. While the lesion may affect all the roots, the upper roots are usually ruptured, whereas the lower roots (if involved) are always avulsed. 3. Spontaneous recovery is possible, but its quality depends on how early recovery of previously paralyzed muscles begins. If the biceps have not started to recover by 3 months, the final result will be poor. It is at this time interval that a surgical decision should be made. 4. Surgical repair is always possible, usually by grafting, though repair can be difficult if significant numbers of avulsions have occurred. 5. The results of surgical reconstruction are better than are the results of spontaneous evolution, at least in those patients who reach the age of 3 months without evidence of recovery of the biceps. For example, more than half of the patients recover a nearly normal shoulder after grafting C5, C6 lesions in Gilbert's series, whereas in the same control population of patients, none achieved this result spontaneously. 6. Palliative treatment of the sequelae of birth palsies is difficult, and the results obtained are rarely totally satisfactory. It is for these reasons that the initial surgical intervention should be on the plexus itself in those instances meeting the criteria established above. It is important to make this decision as quickly as possible before neuroplasticity is diminished and joint contractions have occurred.