Objective The goal of this study was to develop anatomically detailed, finite element (FE) models of the medial and lateral plantar longitudinal arch (MPLA, LPLA), and to investigate bone and muscle stresses resulting from plantar fasciotomy and major plantar ligament injuries. Method Nonlinear FE models of the second ray of MPLA and the fifth ray of LPLA were constructed on the basis of CT and MRI images of Virtual Chinese Human "female No.1". The models assumed a balanced standing load configuration. Three different degrees of passive intrinsic muscle tension(weak, moderate, or severe)were used in conjunction with simulations of plantar ligamentous structure failures. Result Plantar fasciotomy caused von Mises stress increases in the bones and plantar ligaments while major plantar ligament injuries caused stress increases in the bones, flexor tendons, and plantar fascia. Increasing plantar intrinsic muscle passive tensions decreased stress/strain levels in the both arches, and could adjust abnormal tension/compression stress flows of the arches to close to the normal biomechanical states. Conclusions This study shows that plantar longitudinal arches are concordant combination of bony structures, plantar intrinsic muscles, plantar ligaments and plantar fascia. After plantar ligamentous structure failures, plantar intrinsic muscles have to contribute to stabilize the plantar arches. This mechanism may reduce further musculoskeletal damages such as stress fractures and tendonitis.