Acquired adult flat foot, despite numerous research projects, is a controversial clinical entity. Recently the role of plantar calcaneonavicular ligament complex (spring ligament) in stabilization of the longitudinal arch of the foot has drawn an attention. Since there are differences in anatomical description of his complex in the literature, the main aim of our study was to anatomically evaluate this complex. Ten cadaver feet were examined. In four cases spring ligament complex comprised two components: superomedial calcaneonavicular ligament and inferior calcaneonavicular ligament. In six cases complex was composed of three ligaments and we were able to identify structure of the third ligament. In this subgroup in two cases the spring ligament had its own fibrocartilage surface connected by tiny fibrous band with fibrocartilage articular surface. In summary, the spring ligament complex comprises superomedial calcaneonavicular ligament and inferior calcaneonavicular ligament. In majority of cases one can distinguish structure of the third ligament.