Plantar calcaneonavicular ligament


The plantar calcaneonavicular ligament is a complex of three ligaments on the underside of the foot that connect the calcaneus with the navicular bone.

Structure

The plantar calcaneonavicular ligamentous complex is a broad and thick band with three constituent ligaments that connect the anterior margin of the sustentaculum tali of the calcaneus to the plantar surface of the navicular. Its individual components are the superomedial, intermedial and lateral ligaments, which fan out and attach to the navicular bone at three separate locations.
This ligamentous complex not only serves to connect the calcaneus and navicular, but supports the head of the talus, forming part of the articular cavity in which it is received. It helps to maintain the medial longitudinal arch of the foot, and by providing support to the head of the talus, bears most of the body weight in a normally functioning foot. When torn, it can result in a flatfoot deformity, and impair mobility.
The dorsal or superomedial component of the ligament presents a fibrocartilaginous facet, lined by the synovial membrane, upon which a portion of the head of the talus rests. Its plantar surface, consisting of the intermedial and lateral ligaments, is supported by the tendon of the tibialis posterior; its medial border is blended with the forepart of the deltoid ligament of the ankle-joint.