The spring ligament (plantar calcaneonavicular ligament) is the most important passive stabiliser of the medial longitudinal arch, supporting the head of the talus from below at the talonavicular joint. When it fails, the talus plantarflexes and medially rotates, driving the navicular into abduction and producing the characteristic arch collapse of adult-acquired flatfoot. Spring ligament tears are found in the majority of patients with tibialis posterior tendon dysfunction.
| Origin | Sustentaculum tali of the calcaneus |
|---|---|
| Insertion | Plantar and medial surfaces of the navicular |
| Actions | Supports the head of the talus from below; maintains the medial longitudinal arch; resists arch collapse under axial load |
|---|
Spring ligament insufficiency is now recognised as a co-pathology in most cases of tibialis posterior tendon dysfunction and adult-acquired flatfoot. MRI demonstrates spring ligament tears as signal change or discontinuity in the superomedial band. Surgical flatfoot correction increasingly includes spring ligament reconstruction alongside calcaneal osteotomy to address both the dynamic and static components of arch collapse.
Disruption of the plantar calcaneonavicular ligament producing talonavicular joint instability and medial arch collapse, typically found alongside tibialis posterior tendon dysfunction and requiring surgical reconstruction as part of flatfoot correction.
