Erb's palsy contrasted with Klumpke's and total palsy: different mechanisms are involved.

OBJECTIVE

The purpose of this study was to examine the available evidence regarding the nature of the forces that were involved in the production of a lower plexus palsy or a total (whole arm) palsy, as contrasted with the nature of the forces that resulted in an upper plexus palsy.

STUDY

DESIGN

This was a review of studies that dealt with specific mechanisms that were supplemented by reports of total palsy that were gleaned from the literature and case reports from the clinical and medical legal cases of the authors.

RESULTS

Studies of the forces involved in brachial plexus injury in adults and from cadaver studies in infants who were stillborn or who died in the newborn period attest to the nature of the forces needed to damage the lower plexus. This evidence is reinforced by the case reports.

CONCLUSION

Forces other than simple widening of the head-shoulder angle are necessary to disrupt the roots or cords of the lower brachial plexus. The position of the arm and direction of the forces that are applied determine the nature of the lesion.