Unusual Origin of a Double Upper Subscapular Nerve from the Suprascapular Nerve and the Posterior Division of the Upper Trunk of the Brachial Plexus: A Case Report.

A double upper subscapular nerve on the right side was detected in a male cadaver, with the proximal one arising from the suprascapular nerve and the distal one from the posterior division of the upper trunk of the brachial plexus. Both of them penetrated and supplied the uppermost portion of the right subscapularis muscle. That anatomic variation was associated with a median nerve formed by two lateral roots. The origin and pattern of the upper subscapular nerve displays high variability, however the presented combination of the variable origin of a double upper subscapular nerve has rarely been described in the literature. The knowledge of such an anatomic variation is essential for the surgeon operating in the region especially in instances of brachial plexus' repair after any traumatic injury. Moreover, the awareness of the precise origin and topography of these nerves is important for the physician attempting to block these nerves or utilizing these nerves as grafts for neurotization of adjacent damaged nerves of the brachial plexus.