We thank Liotta et al. (2010) for their interest in our recent article (Ang et al., 2010), which we describe an anatomical anomaly of an accessory flexor carpi ulnaris (FCU) muscle belly found incidentally during surgery for elective nerve transfer of the anterior interosseous nerve to innervate the deep branch of the ulnar nerve following traumatic ulnar nerve palsy. We have several comments regarding their letter.
The authors describe the utility of ultrasound in assessing aberrant musculature and in particular the FCU. As mentioned in our article, we performed a wrist ultrasound to identify the aberrant flexor muscle, which was able to clearly identify the aberrant muscle and interestingly a wrist ultrasound of the contralateral side showed demonstrated that the anomaly was bilateral (see Fig. 1).
Although Liotta et al. described their case of FCU atrophy as an anomaly, we believe that their case indicates 'pathology' rather than 'anomaly'. An anatomical anomaly or variation implies an inherent deviation from the norm. We feel that muscle hypoplasia or atrophy, or variation in the size of a muscle belly, can not be considered a true anatomical ''anomaly,'' and more likely represents a pathological process. In defining anatomical anomalies relating to a muscle, Kopsch described seven types (Kopsch, 1908;Kopsch, 1955