Painful, palpable and pathological: anomalous flexor digitorum superficialis brevis in the palm, comparative anatomical context, and an updated classification of anomalies of the flexor digitorum superficialis.

Anomalies of the flexor digitorum superficialis are rare and can present a diagnostic dilemma. Patients present with a painful or palpable mass, or symptoms of carpal tunnel syndrome. This review article summarizes previously reported anomalies of the flexor digitorum superficialis, reports a further case, and proposes a new classification.