Cutaneous nerve to the subacromial region originating from the lateral pectoral nerve

During dissection practice, a cutaneous branch to the deltoid region, which originated from the lateral pectoral nerve, was found bilaterally in one Japanese male (two of 125 sides, 1.6%). The branch originated from the superior surface of the lateral pectoral nerve, ran on the superior surfaces of the coracoid process and the coraco-acromial ligament, and pierced the deltoid muscle close to the tip of the acromion. The distribution area of this cutaneous branch was similar to the cutaneous branch of the suprascapular nerve. Although the branch from the suprascapular nerve has been reported in man and primates, a minute description of such a branch from the lateral pectoral nerve is not currently available in the literature. According to the detailed analyses of the roots of the lateral pectoral nerve and the suprascapular nerve, the roots of both nerves are close to each other in the upper part of the superior trunk of the brachial plexus. Therefore, these cutaneous branches have different courses, but are considered to be a single nerve to complement the supraclavicular nerves.