[Overlooked and unappreciated anatomical facts with regard to the development of pes planus].

Based on careful anatomical praeparations and analyse of fibres the incorrect and incomplet descriptions and illustrations of the calcaneonavicular ligaments are corrected and the deductions for the normal and the pes planus producing processes are concluded. The significance of the "Fibrocartilago navicularis" (BNA) and the manysided efficiency of a vigorous but as yet unnoticed ligaments is discussed.