Variant muscle to the little finger originating from the flexor digitorum superficialis

Introduction Flexor digitorum superficialis (FDS) is the muscle which responsible from the skill actions of the fingers. It has three heads including humeral, ulnar and radial; generally the humeral and ulnar heads are fused together and called as humeroulnar head. The muscle fibers reach the other fingers except the thumb. Each of the muscle beams divides into two parts at the level of the 1st phalanx, and they end at the lateral sides of the middle parts of the middle phalanx. It is innervated by the median nerve. In case of the function loss of this muscle, 2nd phalanx can not make flexion against force. Variations of the muscles of the anterior forearm are common [1,2,3,4,5,6]. The clinicians and the anatomist should know that the variations of FDS are more common than the other antebrachial muscles [7]. Clinical [1] and anatomical [8] studies have revealed variations of the portion of the FDS to the little finger (FDS -V) where the muscle belly is fused with that of the belly to the ring (fourth) finger or lacks a tendon. Even if most variations of FDS have been reported, some details might have been missed. Because of the importance of these anatomic details, we reported this case. Knowledge of such variations may be important during the hand surgery and in the preoperative diagnosis related to the muscles in the front side of the forearm and the tendons passing through the carpal tunnel.