Anatomical variant of the lateral pectoral nerve innervating the anterior portion of the deltoid muscle: A case report

Background: The deltoid muscle is innervated by the axillary nerve. There is no collateral nerve supply described for this muscle. Palsy of the axillary nerve is common in shoulder trauma due to its close relationship to the surgical neck of humerus. Methods: A dissection of the pectoral and axillary regions of two female cadavers was performed bilaterally for a detailed analysis of the innervation of the deltoid muscle. Results: A branch of the lateral pectoral nerve provided supplemental innervation to the anterior portion of the deltoid muscle bilaterally in both cadavers. Conclusion: A branch of the lateral pectoral nerve could provide collateral nerve supply to the deltoid muscle. The frequency of this anatomical variation requires further exploration. (C) 1997 Wiley-Liss, Inc.