Plantar calcaneonavicular ligament (Spring ligament)
This ligament plays an important role in the development of acquired ‘flat foot deformity’ (where the arch is missing) in adults. It has been linked to the stabilization of the foot’s longitudinal arch; this leads to the insufficiency of the spring ligament, which causes it to tear.
The plantar calcaneonavicular ligament complex is different on different feet. Sometimes it is comprised of two ligaments, the inferior calcaneonavicular and the superomedial; however, it most often has a third ligament.