The talus has no tendinous insertions. Its stability (passive only) is dependent on adjacent bones and the ligamentous component (peritalar complex) and includes lateral, medial, anterior, posterior and rotatory stabilisation systems. The medial system alone is nearly always involved in the overall picture of coxa pedis. This is especially true of the plantar calcaneonavicular and the plantar and lateral calcaneocuboid ligaments. Dysplasia of these ligaments, with or without concomitant skeletal ontogenetic dysmorphism, is nearly always a factor underlying the progression of pes valgus in childhood. Coxa pedis closely resembles the hip in morphology, progression and pathology. It is an enarthrotic structure, consisting of the head of the talus on the cephalic side, and the posterior joint surface of the navicular and the anterior and sustentacular surfaces of the calcaneus on the cotyloid side. Stability of the cotyle pedis is provided by the plantar calcaneonavicular, subtended to the intertalar-calcanco-navicular capsule and the cotyloid glcnoid. Stability of the cotyle ensures medial stability of the talus and is due to the stability of the relations between the navicular, calcaneus and cuboid, ensured by medial and lateral ligaments. This is the functional significance of ligaments lateral topographically in medial stabilisation of the talus. Intra-articular stability of the head of the talus in dysmorphism of the coxa may take the form of extreme protrusion of the vertical talus as far as the more or less striking protrusions of progressive pictures of pes valgus in childhood. The main features of this ligament disease of coxa pedis are hypoplasia and laxness of the dorsal and lateral calcancocuboids and the capsule, together with the plantar calcaneonavicular. The clinical equivalents are lateral subluxation of the anterior process of the calcaneus, sometimes with evident callosity of the external region of the tarsus, plus medial detection of the protruded head of the talus. The radiographical picture is one of reduction of the base/height ratio of the talus-calcaneus-navicular triangle. Surgical indications for ligament stabilisation are advanced talar protrusion unaccompanied as yet by stabilised skeletal deformities and reducible, talar subluxation in the transition to protrusion stage, and talar subluxation with calcaneonavicular and subtalar instability. In the first two situations, surgery consists of calcaneonavicular plasty (dorsal and lateral) using half the long peroneal tendon, and intertalar-calcaneo-navicular capsule and ligament plasty. In the last case, dorsal and lateral calcaneonavicular plasty is performed, a new ligament being created out of half the short peroneal tendon.