The authors describe a case of an inborn contracture of the superficial flexors of the three-phalangeal fingers in a 15-year-old girl and treatment of the condition. For clinical purposes a classification on congenital deformities in the proximal part of the flexor complex was proposed in which the described case is included. The classification was derived from the ontogenetic development of flexor tendons. There are three types of deformities: S1 - the muscular belly of the superficial flexor of the fingers is only in the palm; S2 - the muscle is attached to the area between the wrist and medial epicondyle; S3 - the palmaris longus of the fingers is on the medial epicondyle, however the m. palmaris longus is lacking; Pl-1 the superficial flexor exists only in the form of a proximal muscular belly of varying length; Pl-2 - the palmaris longus is on the wrist and the insertion tendon may be thinner than on the contralateral side. The described contracture deformity was classified as type S2.

        Key words: hand, flexor tendons, congenital defects, classification