the necessary flexibility for grasping and climbing in arboreal environments. By contrast, the human foot is unique among great apes in possessing stabilized longitudinal arches in the mid-foot, which impart the necessary stiffness to allow the metatarsals to act as a propulsive lever to enhance the mechanical efficiency of striding bipedalism over relatively uniform terrestrial substrates. In recent years, increased sophistication of biomechanical studies has begun to refine this basic mechanical model of human foot function, noting high levels of anatomical and functional variation within and between human populations and the 'tuneable' functionality of the foot in a variety of contexts (e.g. footwear, terrain, behavior). These developments have not only furthered our understanding of the basic mechanical function of the foot, but delivered new insights into selective pressures that have driven our evolutionary history, how the foot is impacted by aging and disease, and how we might better tackle limb dysfunction through clinical treatment.The goal of the Research Topic "The Human Foot: Function in progress" was to further advance our understanding of how anatomy and function interact and contribute to the They test hypotheses related to the interaction between mechanical and thermodynamic functioning of the heel during foot contact by collecting motion and temperature on humans walking with different magnitudes of added weight. They conclude that a complex array of heat dissipation mechanisms must contribute to the heel's thermodynamics responses during walking, and that additional factors (beside energy dissipation) should be explored in future studies. Together, these papers show that our insight in the functional anatomy of the foot continuously advances thanks to the use of innovative methods, the combination of techniques and expertise from different disciplines, and effective collaboration between researchers.
Editorial17 July 2023
Editorial: The human foot: function in progress
Subtalar instability (STI) is a disabling complication after an acute lateral ankle sprain and remains a challenging problem. The pathophysiology is difficult to understand. Especially the relative contribution of the intrinsic subtalar ligaments in the stability of the subtalar joint is still controversial. Diagnosis is difficult because of the overlapping clinical signs with talocrural instability and the absence of a reliable diagnostic reference test. This often results in misdiagnosis and inappropriate treatment.
Recent research offers new insights in the pathophysiology of subtalar instability and the importance of the intrinsic subtalar ligaments. Recent publications clarify the local anatomical and biomechanical characteristics of the subtalar ligaments. The cervical ligament and interosseous talocalcaneal ligament seem to play an important function in the normal kinematics and stability of the subtalar joint. In addition to the calcaneofibular ligament (CFL), these ligaments seem to have an important role in the pathomechanics of subtalar instability (STI). These new insights have an impact on the approach to STI in clinical practice. Diagnosis of STI can be performed be performed by a step-by-step approach to raise the suspicion to STI. This approach consists of clinical signs, abnormalities of the subtalar ligaments on MRI and peroperative evaluation. Surgical treatment should address all the aspects of the instability and focus on a restoration of the normal anatomical and biomechanical properties. Besides a low threshold to reconstruct the CFL, a reconstruction of the subtalar ligaments should be considered in complex cases of instability.
The purpose of this review is to provide a comprehensive update of the current literature focused on the contribution of the different ligaments in the stability of the subtalar joint. This review aims to introduce the more recent findings in the earlier hypotheses on normal kinesiology, pathophysiology and relation with talocrural instability. The consequences of this improved understanding of pathophysiology on patient identification, treatment and future research are described.
To comparatively investigate the morphological adaptation of the human foot for achieving robust and efficient bipedal locomotion, we develop three-dimensional finite element models of the human and chimpanzee feet. Foot bones and the outer surface of the foot are extracted from computer tomography images and meshed with tetrahedral elements. The ligaments and plantar fascia are represented by tension-only spring elements. The contacts between the bones and between the foot and ground are solved using frictionless and Coulomb friction contact algorithms, respectively. Physiologically realistic loading conditions of the feet during quiet bipedal standing are simulated. Our results indicate that the center of pressure (COP) is located more anteriorly in the human foot than in the chimpanzee foot, indicating a larger stability margin in bipedal posture in humans. Furthermore, the vertical free moment generated by the coupling motion of the calcaneus and tibia during axial loading is larger in the human foot, which can facilitate the compensation of the net yaw moment of the body around the COP during bipedal locomotion. Furthermore, the human foot can store elastic energy more effectively during axial loading for the effective generation of propulsive force in the late stance phase. This computational framework for a comparative investigation of the causal relationship among the morphology, kinematics, and kinetics of the foot may provide a better understanding regarding the functional significance of the morphological features of the human foot.