Which ligament is stretched in a flat foot?

Which ligament is stretched in a flat foot?

• A. Long plantar ligament
• B. Spring (plantar calcaneonavicular)
• C. Deltoid ligament
• D. Plantar fascia

Answer: (B)

The arches of the foot rely on ligaments that hold the bones in place during weight bearing, especially the plantar calcaneonavicular (spring) ligament. This ligament runs from the sustentaculum tali of the calcaneus to the navicular bone and acts like a spring to support the head of the talus, helping maintain the medial longitudinal arch. When it is stretched, the talar head can drop and the medial arch collapses, producing flat foot. The other ligaments play roles in stabilizing different parts of the foot: the long plantar ligament supports the lateral arch, the deltoid ligament stabilizes the ankle medially, and the plantar fascia contributes to arch support via the windlass mechanism but is not the primary structure stretched in pes planus.

The arches of the foot rely on ligaments that hold the bones in place during weight bearing, especially the plantar calcaneonavicular (spring) ligament. This ligament runs from the sustentaculum tali of the calcaneus to the navicular bone and acts like a spring to support the head of the talus, helping maintain the medial longitudinal arch. When it is stretched, the talar head can drop and the medial arch collapses, producing flat foot. The other ligaments play roles in stabilizing different parts of the foot: the long plantar ligament supports the lateral arch, the deltoid ligament stabilizes the ankle medially, and the plantar fascia contributes to arch support via the windlass mechanism but is not the primary structure stretched in pes planus.