Stiffness of the human foot and evolution of the transverse arch.
- 作者列表："Venkadesan M","Yawar A","Eng CM","Dias MA","Singh DK","Tommasini SM","Haims AH","Bandi MM","Mandre S
:The stiff human foot enables an efficient push-off when walking or running, and was critical for the evolution of bipedalism1-6. The uniquely arched morphology of the human midfoot is thought to stiffen it5-9, whereas other primates have flat feet that bend severely in the midfoot7,10,11. However, the relationship between midfoot geometry and stiffness remains debated in foot biomechanics12,13, podiatry14,15 and palaeontology4-6. These debates centre on the medial longitudinal arch5,6 and have not considered whether stiffness is affected by the second, transverse tarsal arch of the human foot16. Here we show that the transverse tarsal arch, acting through the inter-metatarsal tissues, is responsible for more than 40% of the longitudinal stiffness of the foot. The underlying principle resembles a floppy currency note that stiffens considerably when it curls transversally. We derive a dimensionless curvature parameter that governs the stiffness contribution of the transverse tarsal arch, demonstrate its predictive power using mechanical models of the foot and find its skeletal correlate in hominin feet. In the foot, the material properties of the inter-metatarsal tissues and the mobility of the metatarsals may additionally influence the longitudinal stiffness of the foot and thus the curvature-stiffness relationship of the transverse tarsal arch. By analysing fossils, we track the evolution of the curvature parameter among extinct hominins and show that a human-like transverse arch was a key step in the evolution of human bipedalism that predates the genus Homo by at least 1.5 million years. This renewed understanding of the foot may improve the clinical treatment of flatfoot disorders, the design of robotic feet and the study of foot function in locomotion.
: 僵硬的人的脚可以在步行或跑步时有效地推脱，并且对于bipedalism1-6 的进化至关重要。人类中足独特的弓形形态被认为it5-9 变硬，而其他灵长类动物的扁平足在中足 7,10，11 严重弯曲。然而，中足几何形状和僵硬之间的关系在足部生物力学 12 、 13 、podiatry14 、 15 和palaeontology4-6 仍存在争议。这些争论集中在内侧纵弓 5 、 6 上，没有考虑刚度是否受到人体足 16 的第二横跗弓的影响。在这里，我们表明横向跗骨弓，通过跖骨间组织起作用，是足部纵向刚度的 40% 以上的原因。基本原理类似于一种软盘货币，当它横向卷曲时会相当僵硬。我们推导出一个无量纲曲率参数，控制横向跗弓的刚度贡献，使用足部力学模型证明其预测能力，并在hominin足部找到其骨骼相关性。在脚下，跖骨间组织的材料特性和跖骨的移动性可能会额外影响足部的纵向刚度，从而影响横向跗骨弓的曲率-刚度关系。通过分析化石，我们跟踪了灭绝的人类中曲率参数的进化，并表明类人横弓是人类两足动物进化的关键一步，它比Homo属早至少 150万年。。这种对足部的重新认识可能会改善扁平足疾病的临床治疗、机器人足的设计和运动中足功能的研究。
METHODS::Impairments in social cognition have been frequently described in 22q11.2 deletion syndrome (22q11.2DS) and are thought to be a hallmark of difficulties in social interactions. The present study addresses aspects that are critical for everyday social cognitive functioning but have received little attention so far. Sixteen children with 22q11.2DS and 22 controls completed 1 task of facial expression recognition, 1 task of attribution of facial expressions to faceless characters involved in visually presented social interactions, and 1 task of attribution of facial expressions to characters involved in aurally presented dialogues. All three tasks have in common to involve processing of emotions. All participants also completed two tasks of attention and two tasks of visual spatial perception, and their parents completed some scales regarding behavioural problems of their children. Patients performed worse than controls in all three tasks of emotion processing, and even worse in the second and third tasks. However, they performed above chance level in all three tasks, and the results were independent of IQ, age and gender. The analysis of error patterns suggests that patients tend to coarsely categorize situations as either attractive or repulsive and also that they have difficulties in differentiating emotions that are associated with threats. An isolated association between the tasks of emotion and behaviour was found, showing that the more frequently patients with 22q11.2DS perceive happiness where there is not, the less they exhibit aggressive behaviour.
METHODS:BACKGROUND:We describe the first radiographic clinic in the literature for DDH and how this novel clinic can significantly improve the efficiency and cost-effectiveness of service in a tertiary referral centre. AIMS:A radiographic clinic for the management of developmental dysplasia of the hip was introduced in 2017 in our institution. We performed a detailed cost analysis to assess the economic savings made with the introduction of this new clinic. We assessed the efficiency of the service by identifying how many unnecessary outpatient visits were prevented. We also assessed the difference in times from referral to review between the two clinics. METHODS:Analysis of the clinic activity in 2017 was possible as all data was collected prospectively by the DDH CNS and stored in our database. Cost analysis was performed, and the savings made per patient along with the financial benefit to our institution was recorded. RESULTS:The new radiographic clinic reduced the cost of reviewing one patient by €162.51 per patient. There was a 73% discharge rate from the clinic which prevented 251 unnecessary patient visits to the outpatient department over the course of the year. There was a significant 11-day reduction in waiting times between referral and review when comparing the radiographic to the conventional clinic (p < 0.05). CONCLUSIONS:A radiographic clinic for the management of developmental dysplasia of the hip has a significant effect on the efficiency and overall cost-effectiveness of service provision in a tertiary referral centre.
METHODS:INTRODUCTION:Triple pelvic osteotomy (TPO) involves periacetabular osteotomies of the ilium, ischium, and pubis to reorient the acetabulum. This operation is indicated in certain situations for the treatment of developmental dysplasia of the hip, dysplastic neuromuscular hips, and for containment of the femoral head in cases of Legg-Calvé-Perthes disease. METHODS:This retrospective cohort study compares radiographic outcomes of patients who underwent TPO using two different techniques and describes a novel single-incision direct lateral approach. TPO was performed on 22 patients by the senior author. The first 10 patients underwent TPO through a single-incision anterolateral approach. The last 12 patients underwent TPO using the direct lateral approach. Preoperative and postoperative pelvic radiographs were reviewed for each patient, and the migration index and center-edge angle were recorded. RESULTS:The migration index and center-edge angle were evaluated and were not found to be significantly different between the anterolateral and direct lateral groups. The direct lateral approach is described. CONCLUSION:The direct lateral approach for TPO is equivalent to the anterolateral approach on radiographic evaluation. Advantages of the direct lateral approach include direct visualization of the ischial osteotomy, effective mobilization of the acetabulum, and safety of the sciatic nerve.