Carpal tunnel syndrome and trigger finger at the wrist caused by an anomalous flexor digitorum superficialis of the index: a case report and review of literature

Abstract

Carpal tunnel syndrome is usually idiopathic, but many extrinsic or intrinsic processes can cause such a syndrome [1]; anomalies affecting three muscles have been reported to be in relation with carpal tunnel syndrome [2]: hypertrophic or abnormal lumbrical [3–5], palmaris longus and its variants (profundus or reversed) [6–8], and anomalous flexor digitorum superficialis (FDS). In 21 cases of carpal tunnel syndrome, Tanzer described one patient who had FDS which extended completely through the canal [9]. Singer found, in his experience, 147 carpal tunnel release between 1983 and 1993, 74 variations in 60 hands, and introduced a classification of two types for the different anatomic variations [10]. A review of literature revealed that anomalous FDS associated with carpal tunnel syndrome is usually reported, but few cases were described about the association of carpal tunnel and trigger finger at the wrist. A case of a 38-year-old female patient presenting this association secondary to an anomalous FDS muscle belly of the index is described.