An abnormal variation of the brachial plexus with potential clinical significance.

In this case of a male adult Caucasian cadaver, variations were noted involving the location of the CS ventral ramus descending anterior and superolateral to the anterior scalene muscle. An unusual communicating branch was discovered that originated from C5 at the midpoint of the anterior scalene muscle, two centimeters proximal to Erb's point, to communicate with C6 and another communicating branch originating from C6 to C7. Awareness of the possibility of this variation is of great importance during certain surgical procedures. Comparison of this case with the literature is discussed.