Evaluation of Foot Structure in Preschool Children Based on Body Mass

BACKGROUND The human foot has a complex structure and the ligamentous and muscular apparatus undergoes transformation and adaptation during its ontogenetic development. Excessive body mass may be one of the factors disrupting proper foot formation. This study aimed to assess the foot structure in preschool children in relation to body mass. MATERIAL AND METHODS A total of 105 children aged 6.27±0.60 years were examined. Height, weight, and segmental body composition were determined using the Tanita MC-780 body composition analyzer. The foot structure was assessed using the Kasperczyk method, supplemented with digital analysis using the Podoscan 2D camera. The Weisflog index and gamma angle for feet were calculated. Children were divided into 2 groups: children in Group I did not have foot deformities and those in Group II had foot deformities. RESULTS No correlation was observed between body mass and the occurrence of anomalies in foot structure. A correlation was noted between the Weisflog index for the right foot and height in both groups. The Weisflog index for both feet was correlated with BMI, with higher values obtained for the left foot in both groups. In Group II, a correlation was observed between the gamma angle value for the left foot and the predicted muscle mass for the right lower limb, as well as between the same foot and the predicted muscle mass for the left lower limb. CONCLUSIONS No correlation was observed between high BMI and the occurrence of anomalies in foot structure. A relationship was identified between muscle mass and foot structure.

The effect of hallux valgus on the anatomy of the nerves around the first metatarsal bone

OBJECTIVE

To identify the variations in the location of the nerves that may be at risk in hallux valgus (HV) surgery, and to reveal whether these nerves are affected by the anatomical changes associated with HV.

METHOD

In the formalin fixed, 46 lower extremities (19 female, 27 male) (9 normal, 14 mild HV, 21 moderate/severe HV), extensor hallucis longus tendon (EHL), deep plantar artery, medial dorsal cutaneous (MDCN), deep fibular (DFN), common plantar digital (CPDN) and proper plantar digital (PPDN) nerves were examined. The branches of MDCN extending to the medial side of foot were recorded in three segments. The positional topography of nerves according to EHL were analyzed on 360° circle and clock models.

RESULTS

Sex-related differences observed in some parameters in direct measurements were not found in the clock model comparisons. In advanced HV angles (> 20°), DFN was closer to EHL in the distal part of the metatarsal bone, while there was no difference in the proximal. The intersection of the medial branch of the MDCN with the EHL was more proximal in HV cases than in normal feet. The location of the nerves in the clock pattern did not change in HV. Of the nerve branches reaching the medial side of the foot, 65.2% were in Part I, 71.7% in Part II, and 4.3% in Part III.

CONCLUSION

Sex differences in the distance of the nerves to the EHL disappeared when the size effect of the cross-section of the first metatarsal bone region was eliminated with the clock model. Only in advanced HVA (>20°) (not in mild HV), the DFN being closer to the EHL distally and the intersection of the medial branch of the MDCN with the EHL in HV being more proximal than in normal can be interpreted as specific reflections of HV progress. The variations we revealed in the number of branches reaching the inside of the foot may explain the diversity of neuromas or nerve injuries associated with HV surgery.

Anatomical analysis of ligaments surrounding calcaneocuboid joint; implications for role in foot stability

PURPOSE

The calcaneocuboid joint is located in the lateral part of the foot and acts as a major stabilizer for the foot. Injuries to this joint often occur in association with ankle or foot injuries and are frequently overlooked, subsequently causing chronic pain or osteoarthritis. However, the relationship between ligaments surrounding the joint and joint instability remains unclear. Therefore, this study aimed to clarify the morphology and position of the ligaments surrounding the calcaneocuboid joint, and to reveal the relationship between the ligament structure.

METHODS

The position and morphology of the bifurcate ligament (subdivided into calcaneonavicular and calcaneocuboid ligaments), dorsal calcaneocuboid ligament, lateral calcaneocuboid ligament, long plantar ligament, and short plantar ligament were measured (N = 11 feet in 6 Japanese cadavers). The circumference of the joint was quartered, while the ligament-uncovered area and the estimated cross-sectional area of each ligament were compared between the four sides. Furthermore, the estimated cross-sectional area of each ligament was calculated as an index for the ligament strength.

RESULTS

The inferolateral side of the calcaneocuboid joint had the most uncovered area (54.63%) by the ligaments. In addition, the cross-sectional area of the ligaments on the lateral side was considerably smaller than that on the medial side.

CONCLUSION

Our results suggest that ligament weakness on the inferolateral side may cause instability of the calcaneocuboid joint, especially after an inversion sprain injury, and may decrease the lateral longitudinal arch function, which results in chronic foot pain.

Technical note: A volumetric method for measuring the longitudinal arch of human tracks and feet

Fossil footprints (i.e., tracks) were believed to document arch anatomical evolution, although our recent work has shown that track arches record foot kinematics instead. Analyses of track arches can thereby inform the evolution of human locomotion, although quantifying this 3-D aspect of track morphology is difficult. Here, we present a volumetric method for measuring the arches of 3-D models of human tracks and feet, using both Autodesk Maya and Blender software. The method involves generation of a 3-D object that represents the space beneath the longitudinal arch, and measurement of that arch object's geometry and spatial orientation. We provide relevant tools and guidance for users to apply this technique to their own data. We present three case studies to demonstrate potential applications. These include, (1) measuring the arches of static and dynamic human feet, (2) comparing the arches of human tracks with the arches of the feet that made them, and (3) direct comparisons of human track and foot arch morphology throughout simulated track formation. The volumetric measurement tool proved robust for measuring 3-D models of human tracks and feet, in static and dynamic contexts. This tool enables researchers to quantitatively compare arches of fossil hominin tracks, in order to derive biomechanical interpretations from them, and/or offers a different approach for quantifying foot morphology in living humans.

Anthropometric Study of Foot Breadth of 5-10 Years Aged Bangladeshi Children

The present anthropometric study was designed to construct data of 5-10 years aged Bangladeshi children regarding foot breadth and an attempt has been made out to grow interest among the researchers for future study and also to compare the data with the data of the people of other races. This cross-sectional, descriptive and analytic type study was conducted among 5-10 years aged 109 Bangladeshi children (70 male and 39 female) at different areas of Mymensingh district (Fulpur, Muktagacha, Fulbaria, Trisal and Haluaghat), Bangladesh from January 2016 to December 2016. Non-random purposive sampling technique was taken for sample collection. Any kind of foot deformity due to either from congenital or physical injury was excluded to construct standard measurement. Foot breadth was measured using slide caliper. The children were asked to stand with weight distributed equally on both feet. The legs were perpendicular to the feet. The mean foot breadth of right side of 5, 6, 7, 8, 9 and 10 years aged male children were 7.08±.61 cm, 7.11±.30 cm, 7.61±.45 cm, 7.44±.43 cm, 8.12±.38 cm and 8.17±.44 cm respectively and those of female children were 6.55±.64 cm, 7.17±.27 cm, 7.04±.70 cm, 7.62±.54 cm, 7.48±.88 cm and 7.85±.72 cm respectively. The mean foot breadth of left side of 5, 6, 7, 8, 9 and 10 years aged male children were 7.04±.60 cm, 7.03±.30 cm, 7.52±.47 cm, 7.36±.45 cm, 8.03±.38 cm and 8.08±.43 cm respectively and those of female children were 6.46±.63 cm, 7.10±.31 cm, 6.95±.71 cm, 7.54±.52 cm, 7.37±.89 cm and 7.77±.71 cm respectively. Comparison of foot breadth between male and female children was done by Unpaired Students 't' test and the differences of means were statistically non-significant. Data were tabulated and statistically analyzed using Microsoft excel and SPSS software. The results of present study would be useful in anatomy, orthopedics, forensic science, plastic surgery, radiology, podiatry, archeology, anthropology and nutrition science.

Exploring flatfeet morphology in children aged 6-12 years: relationships with body mass and body height through footprints and three-dimensional measurements

The aim of the study was to determine the relationship between flatfoot morphology and body mass and height in children aged 6-12 years. A total of 6471 Chinese children (mean age 9.0 ± 1.9 years, 41% female) were assessed for foot morphometry, body height, and body mass index. Foot morphology, including foot length, width, girth, arch height, hallux valgus angle, and rearfoot valgus angle, was measured using a 3D laser scanner. Flatfoot evaluations were conducted using the Sztriter-Godunov index (KY) from footprints. All measurements were analyzed by age and sex using the mean values of the left and right sides. Comparisons were performed between flatfoot groups, between body mass index (BMI) groups, and between body height groups. The study revealed a significant decrease in the incidence of bipedal flatfoot with age (p < 0.001), whereas the prevalence of obesity remained consistent (p > 0.05). Bipedal flatfoot was associated with distinct morphological changes, including lower arches, reduced instep height, diminished ankle heights and a greater rearfoot valgus angle (p < 0.05). When comparing the BMI groups, overweight children had larger and thicker feet (p < 0.05), but no differences were found in arch height and ankle height (p > 0.05). When comparing the body height groups, short-statured children had a shorter feet girth, shorter arches, and shorter ankle height (p < 0.05), but no differences were found in the rearfoot valgus angle (p > 0.05).

CONCLUSION

The main characteristics of flat feet include lower arches and instep heights and ankle heights but higher rearfoot valgus angles. In general, overweight children's feet do not have the common features of flat feet. In contrast, short children had similar features of flatfoot except for rearfoot valgus. Assessment of posture, such as rearfoot valgus, can be critical in identifying children with flat feet.

WHAT IS KNOWN

• The morphology of children's feet is associated with body growth, but the relationship between flatfeet and body mass and height remains controversial.

WHAT IS NEW

• Three-dimensional foot measurement shows that body mass is generally not associated with flatfeet, while short children have lower arches but no rearfoot valgus.

Anatomical Exploration of the KI1 Acupoint: Implications for Medial and Lateral Plantar Nerve Stimulation

Background and Objectives: This study aims to identify the precise anatomical location and therapeutic mechanisms of the KI1 acupoint (Yongquan) in relation to foot muscles and nerves, known for treating neurological disorders and pain. Materials and Methods: Dissection of six cadavers at Chungnam National University College of Medicine examined KI1's relation to the foot's four-layer structure. Results: The KI1 acupoint was located in the superficial and deep layers of the plantar foot, adjacent to significant nerves like the medial and lateral plantar nerves. Differences in the acupoint's exact location between genders were noted, reflecting variances in foot morphology. KI1 acupuncture was found to stimulate the muscle spindles and nerve fibers essential for balance and bipedal locomotion. This stimulation may enhance sensory feedback, potentially improving cognitive functions and balance control. Conclusions: This anatomical insight into KI1 acupuncture underpins its potential in neurological therapies and pain management.

Fit of fire boots: exploring internal morphology using computed tomography

Fit of fire boots is a crucial factor in the safety and performance of firefighters on the hostile fireground. Firefighters have reported that ill-fitting fire boots restrict their lower body movement and sometimes cause very dangerous situations by falling off behind the wearer. By using computed tomography, this study demonstrates the potential to quantify and visualize the fit of fire boots, which previously relied on subjective feedback from the wearers. The high-resolution three-dimensional (3D) models of two fire boot products allowed a detailed observation and measurement of the internal space of the boots. Also, the boot's internal dimension was compared to the foot measurement of local firefighters, showing the significant differences between the two boots. Lastly, simulation wrapping the 3D scanned foot with the boot revealed large void spaces around the toe box and ankle, as well as the narrower ball width of the boot than the foot.

Morphological variability of the fibularis brevis tendon in human fetuses

INTRODUCTION

The morphological variability of the fibularis brevis tendon in adults is well known. However, studies on its classification in the human fetus do not exist. The aim of this study was to provide the first comprehensive classification of the fibularis brevis tendon based on its insertion in human fetuses. The second aim of the study is to evaluate the prevalence of fibularis digiti quinti.

MATERIAL AND METHODS

Forty-three spontaneously aborted human fetuses were studied (21 male, 22 female, 86 lower limbs). All were from a Central European population), aged 18-38 weeks of gestation at the time of death.

RESULTS

Three main types of fibularis brevis tendon were distinguished. The most common was Type I (77%), characterized by a single distal attachment. The tendon was attached to the tuberosity at the base of the fifth metatarsal, on the lateral side. The second most common was Type II (19%) - a bifurcated distal attachment. The main tendon was attached to the tuberosity at the base of the fifth metatarsal on the lateral side. Based on the attachment site of the accessory tendon, four subtypes were determined: Type IIA - the accessory tendon attached to the dorsal surface of the base of the fifth metatarsal. At the side of attachment, the fibularis brevis tendon was connected with a portion of the fibularis tertius tendon. Type IIB - the accessory tendon attached to the proximal part of the shaft of the fifth metatarsal. Type IIC - the accessory tendon was attached to the fascia covering the fourth interosseous space. Type IID - the accessory tendon was fused with fibularis longus tendon. Type III is the rarest (4%) - triple branched distal attachment. The main tendon was attached to the tuberosity at the base of the fifth metatarsal. The first accessory tendon was attached to the proximal part of the shaft of the fifth metatarsal, and the second accessory tendon was attached to the fascia covering the fourth interosseous space. The fibularis digiti quinti was present in 24 feet (28%) of the 86 lower limbs dissected.

CONCLUSION

The fibularis brevis is characterized by high morphological variability. The proposed classification consists of three main Types (I-III), with Type II divided into subtypes (A-D). The fibularis digiti quinti is not closely related to the type of fibularis brevis tendon.

Tracking 'transitional' diadectomorphs in the earliest Permian of equatorial Pangea

Diadectomorpha was a clade of large-bodied stem-amniotes or possibly early-diverging synapsids that established a successful dynasty of late Carboniferous to late Permian high-fiber herbivores. Aside from their fairly rich record of body fossils, diadectomorphs are also well-known from widely distributed tracks and trackways referred to as Ichniotherium. Here, we provide detailed description of a diadectomorph trackway and a manus-pes couple originating from two different horizons in the Asselian (lowermost Permian) of the Boskovice Basin in the Czech Republic. The specimens represent two distinct ichnotaxa of Ichniotherium, I. cottae and I. sphaerodactylum. Intriguingly, the I. cottae trackway described herein illustrates a 'transitional' stage in the posture evolution of diadectomorphs, showing track morphologies possibly attributable to a Diadectes-like taxon combined with distances between the successive manus and pes imprints similar to those observable in earlier-diverging diadectomorphs, such as Orobates. In addition, this trackway is composed of 14 tracks, including six well-preserved manus-pes couples, and thus represents the most complete record of Ichniotherium cottae described to date from the Asselian strata. In turn, the manus-pes couple, attributed here to I. sphaerodactylum, represents only the second record of this ichnotaxon from the European part of Pangea. Our study adds to the diversity of the ichnological record of Permian tetrapods in the Boskovice Basin which had been essentially unexplored until very recently.

The oldest fossil bird-like footprints from the upper Triassic of southern Africa

Footprint morphology reflects the anatomy of the trackmaker's foot and is direct evidence for the animal's behaviour. Consequently, fossil tracks can be used to infer ancient diversity, ethology, and evolutionary trends. This is particularly useful for deep-time intervals during which the early history of an animal group is reliant upon limited fossil skeletal material. Fossil tracks of early birds and theropods, the co-existing dinosaurian ancestors of birds, co-occur in the rock record since the Early Cretaceous. However, the evolutionary transition from dinosaur to bird and the timing of the birds' origin are still contested. Skeletal remains of the basal-most birds Aurornis, Anchiornis, Archaeopteryx and Xiaotingia are Middle to Late Jurassic, while tracks with tentative bird affinities, attributed to dinosaurs, are known from as early as the Late Triassic. Here, we present numerous, well-provenanced, Late Triassic and Early Jurassic tridactyl tracks from southern Africa, with demonstrable bird-like affinities, predating basal bird body fossils by c. 60 million years.

Morphological and evolutionary insights into the keystone element of the human foot's medial longitudinal arch

The evolution of the medial longitudinal arch (MLA) is one of the most impactful adaptations in the hominin foot that emerged with bipedalism. When and how it evolved in the human lineage is still unresolved. Complicating the issue, clinical definitions of flatfoot in living Homo sapiens have not reached a consensus. Here we digitally investigate the navicular morphology of H. sapiens (living, archaeological, and fossil), great apes, and fossil hominins and its correlation with the MLA. A distinctive navicular shape characterises living H. sapiens with adult acquired flexible flatfoot, while the congenital flexible flatfoot exhibits a 'normal' navicular shape. All H. sapiens groups differentiate from great apes independently from variations in the MLA, likely because of bipedalism. Most australopith, H. naledi, and H. floresiensis navicular shapes are closer to those of great apes, which is inconsistent with a human-like MLA and instead might suggest a certain degree of arboreality. Navicular shape of OH 8 and fossil H. sapiens falls within the normal living H. sapiens spectrum of variation of the MLA (including congenital flexible flatfoot and individuals with a well-developed MLA). At the same time, H. neanderthalensis seem to be characterised by a different expression of the MLA.

Proximity of percutaneous tibial nerve stimulation needle insertion to surrounding anatomic structures: a cadaveric study

BACKGROUND

Percutaneous tibial nerve stimulation is a third-line treatment for overactive bladder and urgency urinary incontinence. During the procedure, a needle is inserted cephalad to the medial malleolus and posterior to the tibia. In recent years, permanent implants and leads have been developed for insertion into the medial ankle via a small incision. There are many important structures present in the medial compartment of the ankle, including the great saphenous vein, saphenous nerve, tibial nerve, posterior tibial vessels, and tendons of the posterior compartment leg muscles.

OBJECTIVE

The primary objective of this study was to identify the proximity of the percutaneous tibial nerve stimulation needle placed per Food and Drug Administration-approved device instructions to nearby important anatomic structures. The secondary objectives were to identify the proximity of the tibial nerve to the needle site, identify clinically relevant ankle anatomic structures, and confirm the tibial nerve and posterior tibial vasculature by histologic analysis.

STUDY DESIGN

Detailed medial ankle dissections were performed bilaterally on 10 female lightly embalmed anatomic donors (cadavers) obtained from the Willed Body Program at the University of Louisville. A pin was inserted at the percutaneous tibial nerve stimulation needle site, and the medial ankle was minimally dissected so the surrounding anatomic structures were visible but not disrupted. The shortest distance from the pin to the selected structures of the medial ankle region was measured. On completion of each dissection and set of measurements, tissue was harvested for histologic examination. The distances between the pin and each structure were assessed using means and standard deviations. A paired t test was used to assess the difference in the locations between the left and right ankles. Statistical analysis was performed on left-sided, right-sided, and combined measurements. An 80% prediction interval was found to represent the expected range of values for the measurement of a new cadaver or patient, and the 95% confidence interval of the mean was computed to characterize the average distance across all cadavers or patients.

RESULTS

The medial ankle of 10 adult female lightly embalmed cadavers were examined bilaterally. Dissections were completed from October 2021 to July 2022. Of note, 80% prediction intervals for the tibial nerve, the posterior tibial artery or vein, and the flexor digitorum longus tendon had a lower range of 0.0 mm from the pin and extending to 12.1, 9.5, and 13.9 mm, respectively. Moreover, 2 of the structures were found to be asymmetrical between the right and left ankles. The great saphenous vein was further from the pin on the left (20.5 mm [standard deviation of 6.4 mm] on the left vs 18.1 mm [standard deviation of 5.3 mm] on the right; P=.04). The calcaneal (Achilles) tendon was further from the pin on the right side (13.2 mm [standard deviation of 6.8 mm] vs 7.9 mm [standard deviation of 6.7 mm]; P=.04). Tibial neurovascular structures were confirmed with microscopic analysis.

CONCLUSION

The anatomic structures within the medial ankle lie unexpectedly close to the percutaneous tibial nerve stimulation needle site as noted per Food and Drug Administration-approved device instructions. There is a possibility that some medial ankle structures are not symmetrical. It is crucial that practitioners understand medial ankle anatomy when performing percutaneous tibial nerve stimulation or permanent device insertion.

Automated plantar contact area estimation in a dynamic state using K-Means clustering

BACKGROUND

Estimation of plantar contact area (PCA) can be used for a variety of purposes such as classification of foot types and diagnosis of foot abnormalities. While some techniques have been developed for assessing static PCA, understanding dynamic PCA may improve understanding of gait biomechanics. This study aims (1) to develop an approach to estimate PCA from video images of footprints during walking and (2) to assess the accuracy and generalizability of this method.

METHODS

A sample of 41 ambulatory, young adults (age = 24.3 ± 3.2 years, mass = 67.2 ± 16.9 kg, height = 1.63 ± 0.08 m) completed 10 trials walking on a raised transparent plexiglass platform. Foot contact during walking was recorded using a video camera placed under the platform. An image processing algorithm, Clustering Segmentation, was developed based on identifying color intensity between the PCA and the rest of the foot and plantar contact morphology.

RESULTS

The proposed approach was compared to manual hand tracing, which is widely accepted as the Gold Standard, as well as with an earlier automated approach (Lidstone et al., 2019). Results showed that Clustering Segmentation followed the Gold Standard closely in all phases of gait. The maximum PCA and the maximum PCA length and width generally increased with foot size, indicating that the algorithm could successfully estimate the PCA across a wide range of foot sizes. Results also showed that the proposed approach for obtaining the PCA may be used to characterize various foot types in a dynamic state.

CONCLUSION

Clustering Segmentation algorithm eliminates the need for subjective interpretation of the PCA. The results showed that the algorithm was considerably faster and more accurate than the earlier automated method. The proposed algorithm will be appropriate for assessment of foot abnormalities and provides complementary information to gait analysis.

Anatomical study of the distal course of the posterior tibial artery: A cadaver study

OBJECTIVE

This study aimed to describe the course, branches, and variances of the posterior tibial artery, which provides the arterial supply of the plantar surface of the foot, starting from the tarsal tunnel level to provide descriptive information for all surgical interventions, diagnostic radiological procedures, and promising endovascular therapies in the tarsal region.

METHODS

In this study, a dissection of 48 feet was performed on 25 formalin-fixed cadavers (19 males and 6 females). Surgical instruments and a digital caliper were used for dissection and measurements, and the critical structures were recorded by a Canon 250D camera to be illustrated later.

RESULTS

All parameters were significantly longer in male cadavers compared to females. According to the correlation analysis, while there was a significant and robust correlation between the axial line and pternion-deep plantar arch (R=.830, P .05), a moderate correlation was found between the axial line and sphyrion-bifurcation (R=.575; P < .05), axial line and deep plantar arch-2nd interdigital commissure (R=.457; P < .05), and sphyrion-bifurcation and pternion-deep plantar arch (R=.480; P < .05). Variation in any branch of the posterior tibial artery was observed in 27 of the 48 studied sides.

CONCLUSION

In our study, the branching and variability of posterior tibial artery on the plantar surface of the foot were described in detail with the determined parameters. In conditions that cause tissue and function loss and require reconstruction, such as diabetes mellitus and atherosclerosis, the most critical factor in increasing treatment success is a better understanding of the region's anatomy.

Effects of obesity and foot arch height on gait mechanics: A cross-sectional study

Foot arch structure contributes to lower-limb joint mechanics and gait in adults with obesity. However, it is not well-known if excessive weight and arch height together affect gait mechanics compared to the effects of excessive weight and arch height alone. The purpose of this study was to determine the influences of arch height and obesity on gait mechanics in adults. In this study, 1) dynamic plantar pressure, 2) spatiotemporal gait parameters, 3) foot progression angle, and 4) ankle and knee joint angles and moments were collected in adults with normal weight with normal arch heights (n = 11), normal weight with lower arch heights (n = 10), obesity with normal arch heights (n = 8), and obesity with lower arch heights (n = 18) as they walked at their preferred speed and at a pedestrian standard walking speed, 1.25 m/s. Digital foot pressure data were used to compute a measure of arch height, the Chippaux-Smirak Index (CSI). Our results revealed that BMI and arch height were each associated with particular measures of ankle and knee joint mechanics during walking in healthy young adults: (i) a higher BMI with greater peak internal ankle plantar-flexion moment and (ii) a lower arch height with greater peak internal ankle eversion and abduction moments and peak internal knee abduction moment (i.e., external knee adduction moment). Our results have implications for understanding the role of arch height in reducing musculoskeletal injury risks, improving gait, and increasing physical activity for people living with obesity.

Evolutionary trends of the lateral foot in catarrhine primates: Contextualizing the fourth metatarsal of Australopithecus afarensis

In 2000, a complete fourth metatarsal (Mt4) of the ∼3- to 4-Million-year-old hominin Australopithecus afarensis was recovered in Hadar, Ethiopia. This metatarsal presented a mostly human-like morphology, suggesting that a rigid lateral foot may have evolved as early as ∼3.2 Ma. The lateral foot is integral in providing stability during the push off phase of gait and is key in understanding the transition to upright, striding bipedalism. Previous comparisons of this fossil were limited to Pan troglodytes, Gorilla gorilla, and modern humans. This study builds on previous studies by contextualizing the Mt4 morphology of A. afarensis (A.L. 333-160) within a diverse comparative sample of nonhuman hominoids (n = 144) and cercopithecids (n = 138) and incorporates other early hominins (n = 3) and fossil hominoids that precede the Pan-Homo split (n = 4) to better assess the polarity of changes in lateral foot morphology surrounding this divergence. We investigate seven morphological features argued to be functionally linked to human-like bipedalism. Our results show that some human-like characters used to assess midfoot and lateral foot stiffness in the hominin fossil record are present in our Miocene ape sample as well as in living cercopithecids. Furthermore, modern nonhuman hominoids can be generally distinguished from other species in most metrics. These results suggest that the possession of a rigid foot in hominins could represent a conserved trait, whereas the specialized pedal grasping mechanics of extant apes may be more derived, in which case some traits often used to infer bipedal locomotion in early hominins may, instead, reflect a lower reliance on pedal grasping. Another possibility is that early hominins reverted from modern ape Mt4 morphology into a more plesiomorphic condition when terrestrial bipedality became a dominant behavior. More fossils dating around the Pan-Homo divergence time are necessary to test these competing hypotheses.

Sexing white 2D footprints using convolutional neural networks

Footprints are left, or obtained, in a variety of scenarios from crime scenes to anthropological investigations. Determining the sex of a footprint can be useful in screening such impressions and attempts have been made to do so using single or multi landmark distances, shape analyses and via the density of friction ridges. Here we explore the relative importance of different components in sexing two-dimensional foot impressions namely, size, shape and texture. We use a machine learning approach and compare this to more traditional methods of discrimination. Two datasets are used, a pilot data set collected from students at Bournemouth University (N = 196) and a larger data set collected by podiatrists at Sheffield NHS Teaching Hospital (N = 2677). Our convolutional neural network can sex a footprint with accuracy of around 90% on a test set of N = 267 footprint images using all image components, which is better than an expert can achieve. However, the quality of the impressions impacts on this success rate, but the results are promising and in time it may be possible to create an automated screening algorithm in which practitioners of whatever sort (medical or forensic) can obtain a first order sexing of a two-dimensional footprint.

Factors Associated With Lower Limb Injuries in Recreational Runners: A Cross-Sectional Survey Including Mental Aspects and Sleep Quality

Knowledge about prevalence and etiology of running-related injuries (RRIs) is important to design effective RRI prevention programs. Mental aspects and sleep quality seem to be important potential risk factors, yet their association with RRIs needs to be elucidated. The aims of this study are to investigate the epidemiology of RRIs in recreational runners and the association of mental aspects, sleep, and other potential factors with RRIs. An internet-based questionnaire was sent to recreational runners recruited through social media, asking for personal and training characteristics, mental aspects (obsessive passion, motivation to exercise), sleep quality, perceived health, quality of life, foot arch type, and RRIs over the past six months. Data were analyzed descriptively and using logistic regression. Self-reported data from 804 questionnaires were analyzed. Twenty-five potential risk factors for RRIs were investigated. 54% of runners reported at least one RRI. The knee was the most-affected location (45%), followed by the lower leg (19%). Patellofemoral pain syndrome was the most-reported injury (20%), followed by medial tibial stress syndrome (17%). Obsessive passionate attitude (odds ratio (OR):1.35; 95% confidence interval (CI):1.18-1.54), motivation to exercise (OR:1.09; CI:1.03-1.15), and sleep quality (OR:1.23; CI:1.15-1.31) were associated with RRIs, as were perceived health (OR:0.96; CI:0.94-0.97), running over 20 km/week (OR:1.58; CI:1.04-2.42), overweight (OR:2.17; CI:1.41-3.34), pes planus (OR:1.80; CI:1.12-2.88), hard-surface running (OR:1.37; CI:1.17-1.59), running company (OR:1.65; CI:1.16-2.35), and following a training program (OR:1.51; CI:1.09-2.10). These factors together explained 30% of the variance in RRIs. A separate regression analysis showed that mental aspects and sleep quality explain 15% of the variance in RRIs. The association of mental aspects and sleep quality with RRIs adds new insights into the multifactorial etiology of RRIs. We therefore recommend that besides common risk factors for RRI, mental aspects and sleep be incorporated into the advice on prevention and management of RRIs.

On the morphological relations of the Achilles tendon and plantar fascia via the calcaneus: a cadaveric study

Current treatments of plantar fasciitis are based on the premise that the Achilles tendon (AT) and plantar fascia (PF) are mechanically directly linked, which is an area of debate. The aim of this study was to assess the morphological relationship between the AT and PF. Nineteen cadaveric feet were x-ray imaged, serially sectioned and plastinated for digital image analyses. Measurements of the AT and PF thicknesses and cross-sectional areas (CSA) were performed at their calcaneal insertion. The fiber continuity was histologically assessed in representative subsamples. Strong correlations exist between the CSA of the AT and PF at calcaneal insertion and the CSA of PF's insertional length (r = 0.80), and between the CSAs of AT's and PF's insertional lengths. Further correlations were observed between AT and PF thicknesses (r = 0.62). This close morphological relationship could, however, not be confirmed through x-ray nor complete fiber continuity in histology. This study provides evidence for a morphometric relationship between the AT and PF, which suggests the presence of a functional relationship between these two structures following the biological key idea that the structure determines the function. The observed morphological correlations substantiate the existing mechanical link between the AT and PF via the posterior calcaneus and might explain why calf stretches are a successful treatment option for plantar heel pain.

Fine-wire electromyography of the transverse head of adductor hallucis during locomotion

BACKGROUND

Previous literature on the transverse head of adductor hallucis (AddH-T) has largely focused on muscle morphology. This data provides insight into muscle architecture, yet fails to inform it's functional implication during walking. The role of the AddH-T, which runs parallel to the distal transverse metatarsal arch, has never been studied using fine-wire EMG during locomotion.

RESEARCH QUESTION

The purpose of this study is to explain a novel method of recording fine-wire EMG of the adductor hallucis muscle of the foot, and secondly, to report phasic AddH-T muscle activity during level walking on hard and soft surfaces.

METHODS

Ultrasound-guided fine-wire EMG was recorded from the AddH-T of each foot, in ten asymptomatic young adults. Participants completed ten walking trials per experimental conditions (hard and soft surface). Ensemble averages were calculated from the time normalized linear-envelopes of each participant, and represented from 0 to 100 percent of the gait cycle.

RESULTS

Using the described ultrasound-guided fine-wire protocol, successful EMG signals were generated in 19 of 20 feet. When walking over hard or soft flooring, the AddH-T muscle has two bursts in EMG, occurring between 0-20 % and 50-65 % of the gait cycle. The magnitude of peak activity was often reduced at initial contact when walking over foam. 45 % of participants experienced a third burst in EMG activity at midstance, corresponding to 30-40 % of the gait cycle.

SIGNIFICANCE

This study has successfully explained a novel method of recording finewire electromyography (EMG) of the adductor hallucis (transverse head) muscle of the foot. Results suggest that the AddH-T stabilizes the forefoot at initial contact and toeoff, while further anchoring the hallux during propulsion. These results provide preliminary insight into the functional role of the AddH-T during human locomotion.

Tandem gait test performance in healthy, physically active adults: Clinical implications for concussion evaluation

OBJECTIVES

To identify factors affecting performance on the tandem gait test in healthy, physically active adults.

DESIGN

Cross-sectional.

METHODS

Participants completed the tandem gait test according to Sport Concussion Assessment Tool 3 (SCAT3) guidelines. Dependent variables included time for best trial (initial 3m, turn, final 3m and total) and whether the trial was "pass" or "fail". Independent variables included sex, concussion history, foot length, height and total number of trials.

RESULTS

55% (35/64) of participants passed the first trial of the tandem gait test; 19% (12/64) had a best time <14s. Sex and concussion history did not affect performance (p>0.05). There were no differences in turn times for those with and without a history of concussion (t=0.26, p=0.80). The number of trials was not significantly correlated with best time (þ=-0.04, p=0.74). There were low (þ=-0.31) to negligible (þ<0.30) correlations between foot length, height and all portions of the test. There was more variability in times for the turn (COV=27%) than during the straight portions (COV=18%).

CONCLUSIONS

Current recommendations for the tandem gait test led to a high false-positive rate in healthy, physically active adults. Sex, concussion history, number of trials and foot length had little to no influence on scores on the test. Turning times were more variable than times on the straight portions of the test. Clinicians may use these results as a guideline when interpreting performance on the tandem gait test in healthy physically active adults.

Relationship of Limb Lengths and Body Composition to Lifting in Weightlifting

Weightlifting is a discipline where technique and anthropometric characteristics are essential to achieve the best results in competitions. This study aims to analyse the relationships between body composition, limb length and barbell kinematics in the performance of weightlifters. It consists of an observational and descriptive study of 19 athletes (12 men [28.50 ± 6.37 years old; 84.58 ± 14.11 kg; 176.18 ± 6.85 cm] and 7 women [27.71 ± 6.34 years old; 64.41 ± 7.63 kg; 166.94 ± 4.11 cm]) who met the inclusion criteria. A level I anthropometrist took anthropometric measures according to the methodology of the International Society for the Advancement of Kinanthropometry (ISAK), and the measurement of the barbell velocity was made with the software Kinovea. In terms of body composition, both genders are within the percentage range of fat mass recommended for this sport. In female weightlifters, there is a positive correlation between foot length, maximal velocity in the Snatch (ρ = 0.775, p = 0.041), and performance indicator in the Snatch and the Clean & Jerk (ρ = 0.964, p < 0.001; ρ = 0.883, p = 0.008, respectively). In male weightlifters, a positive correlation between tibial length and average velocity of the barbell in the Snatch is observed (ρ = 0.848, p < 0.001). Muscle mass percentage correlates positively with performance indicator in both techniques (ρ = 0.634, p = 0.027; ρ = 0.720, p = 0.008). Also, the relative length of the upper limb is negatively correlated with the performance indicator (ρ = −0.602, p = 0.038). Anthropometry and body composition may facilitate skill acquisition among this sport population, contributing to increase the limited body of scientific knowledge related to weightlifting.

Tendinopathies of the foot and the ankle : from the anatomy to the clinic

The tendons of the foot and the ankle are divided into four compartments (posterior, medial, lateral and anterior). They can be the seat of tendinopathies. The term of "tendonopathy" was proposed in 1998 to group the clinical syndrome defined by pain, tendon edema and functional disability. Tendinopathies can be of traumatic origin, inflammatory and we speak about tendinitis, mechanical by hypersollicitation or iatrogenic. The diagnosis of these tendinopathies requires a precise knowledge of the basic anatomical notions and is based on three positive signs, which are the direct tendon palpation pain, passive tendon stretching pain and pain in the contraction of the muscle. The calcaneal tendonopathy is the most frequent.

Location of the Deep Plantar Artery: A Cadaveric Study

BACKGROUND

The deep plantar (D-PL) artery originates from the dorsalis pedis artery in the proximal first intermetatarsal space, an area where many procedures are performed to address deformity, traumatic injury, and infection. The potential risk of injury to the D-PL artery is concerning. The D-PL artery provides vascular contribution to the base of the first metatarsal and forms the D-PL arterial arch with the lateral plantar artery.

METHODS

In an effort to improve our understanding of the positional relationship of the D-PL artery to the first metatarsal, dissections were performed on 43 embalmed cadaver feet to measure the location of the D-PL artery with respect to the base of the first metatarsal. Digital images of the dissected specimens were acquired and saved for measurement using in-house software. Means, standard deviations, and 95% confidence intervals (CIs) were calculated for all of the measurement parameters.

RESULTS

We found that the origin of the D-PL artery was located at a mean ± SD of 11.5 ± 3.9 mm (95% CI, 4.5-24.7 mm) distal to the first metatarsal base and 18.6% ± 6.5% (95% CI, 8.1%-43.4%) of length in reference to the proximal base. The average interrater reliability across all of the measurements was 0.945.

CONCLUSIONS

This study helps clarify the anatomical location of the D-PL artery by providing parameters to aid the surgeon when performing procedures in the proximal first intermetatarsal space. Care must be taken when performing procedures in the region to avoid unintended vascular injury to the D-PL artery.

Backpacks Effect on Foot Posture in Schoolchildren with a Neutral Foot Posture: A Three-Year Prospective Study

Background: There is a paucity of data on the relationship between backpack use and foot posture in children. The aim of this study was to assess the effects of a backpack on foot posture in children with neutral foot posture during three years of follow-up. Methods: A prospective longitudinal observational study was conducted in a sample of 627 children with neutral foot. For each participant included in the study, age, sex, weight, height, body mass index, type of schoolbag (backpack or non-backpack), foot shape, metatarsal formula and type of shoes were recorded. Foot posture was described by the mean of the foot posture index (FPI) and reassessed after three years in a follow-up study. Results: The average age of the children was 8.32 ± 1.32 years. A total of 458 used a backpack when going to school. Over the three-year follow-up period, 50 children who had neutral foot developed supinated foot (n = 18) or pronated foot (n = 32). Univariate and multivariate analysis showed that the children using a backpack were at a higher risk of developing pronated foot (adjusted Odds Ratio (aOR) = 2.05, 95% IC: 1.08–3.89, p = 0.028). Backpack use was not associated with the change from neutral foot to supinated foot. Conclusions: We found a positive association between using a backpack and the risk of developing pronated but not supinated foot. Clinical trials should be conducted to analyze the effect of backpack use on the foot among schoolchildren.

Intrinsic Muscle Flaps for Coverage of Small Defects in the Foot

Exposure of critical structures such as joints, bones, ligaments, and tendons necessitates expeditious closure. The longer these structures remain open to the environment, the higher the risk is for that patient developing osteomyelitis and an amputation. Muscle flaps remain often first choice when dealing with bone infections associated with osteomyelitis, soft tissue infections, and large cavities. Foot defects are a challenge especially in the absence of microsurgical expertise. Intrinsic local flaps of the foot can be an option to cover defects. This article describes local intrinsic muscle flaps for coverage of foot defects.

Neurodynamic modeling of the fruit fly Drosophila melanogaster

This manuscript describes neuromechanical modeling of the fruit fly Drosophila melanogaster in the form of a hexapod robot, Drosophibot, and an accompanying dynamic simulation. Drosophibot is a testbed for real-time dynamical neural controllers modeled after the anatomy and function of the insect nervous system. As such, Drosophibot has been designed to capture features of the animal's biomechanics in order to better test the neural controllers. These features include: dynamically scaling the robot to match the fruit fly by designing its joint elasticity and movement speed; a biomimetic actuator control scheme that converts neural activity into motion in the same way as observed in insects; biomimetic sensing, including proprioception from all leg joints and strain sensing from all leg segments; and passively compliant tarsi that mimic the animal's passive compliance to the walking substrate. We incorporated these features into a dynamical simulation of Drosophibot, and demonstrate that its actuators and sensors perform in an animal-like way. We used this simulation to test a neural walking controller based on anatomical and behavioral data from insects. Finally, we describe Drosophibot's hardware and show that the animal-like features of the simulation transfer to the physical robot.

Children with Obesity Experience Different Age-Related Changes in Plantar Pressure Distributions: A Follow-Up Study in China

Age is a key factor in plantar pressure distributions during the development of obese children. However, the existing evidence for age-related plantar pressures of obese children is not sufficient to make clear how the plantar pressures would change with the increasing age. This study aimed to evaluate the plantar pressure redistributions of obese children after a three-year follow-up and to further compare these changes with normal-weighted children. Ten obese children and eleven normal-weighted counterparts were involved in this study. Plantar pressure measurements were undertaken using a Footscan^® plantar pressure plate on two test sessions three years apart. Peak pressure, pressure-time integral, standard maximum force, and z-scores of these variables were analyzed. Loading transference analyses were applied to detect the different loading transferring mechanisms between obese and normal-weighted children. Significantly increased plantar pressures were observed at the lateral forefoot and midfoot for obese children, which gradually deviated from those of normal-weighted children over the 3 years. With the increasing age, obese children displayed a lateral loading shift at the forefoot in contrast to the normal-weighted. Early interventions are cautiously recommended for obese children before the plantar loading deviation gets worse as they grow older.

Study on bio-inspired feet based on the cushioning and shock absorption characteristics of the ostrich foot

As the main actuator of high-speed running, the ostrich feet are highly capable of cushioning and shock absorption. In this study, based on the elastic modulus scales and assembly order of the 3rd toe soft tissues and the functions of the metatarsophalangeal (MTP) joint, we designed fourteen bio-inspired feet. The impact process on loose sand was simulated on the finite element software Abaqus. Also the stress distributions and deformations of each component of the bio-inspired feet were clarified. With the peak acceleration as the index, the cushioning performances of the bio-inspired feet were compared on both loose sand and solid ground through height-variable impact tests. The 15-15-15 HA (hardness unit) bio-inspired foot showed lower peak acceleration and thereby better cushioning performance, but larger deformation, less-uniform stress distribution and thereby lower stability than the 15-35-55 HA bio-inspired foot. In fact, the silicon rubbers with different hardness degrees (which simulate the elasticity modulus scales of the digital cushions, fascia and skin) and the spring mechanism (which simulates the functions of the MTP joint) work as an “integrated system” of cushioning and shock absorption.

The shape of the transverse arch in high heels while standing

Introduction

High heeled shoes have long been worn in society and they are known to cause biomechanical imbalances to not only the foot, but the whole musculoskeletal system. This study aims to show the detailed changes that happen to the shape of the transverse arch of the foot in high heels, using two different inclination degrees.

Methods

68 women participated in this study. Two custom-made high heels were made with inclinations of 15 degrees and 30 degrees (cm). A weight-bearing ultrasound was used to assess the coronal view of the transverse arch in standing. ANOVA and Tuckey tests were used to compare the results between 0 degrees, 15 degrees and 30 degrees inclinations.

Results

The transverse arch height was slightly increased as the heel height increased (0DI-15DI: p = 0.5852 / 15DI-30DI: p = 0.395 / 0DI-30DI: p = 0.0593). The transverse arch length (0DI-15DI: p = 0.0486 / 15DI-30DI: p = 0.0004 / 0DI-30DI: p = 0.1105) and the area under the metatarsal heads (0DI-15DI: p = 0.0422 / 15DI-30DI: p = 0.0180 / 0DI-30DI: p = 0.9463) significantly decreased as the heel height increased.

Discussion

The main changes were viewed in the 30 degrees inclinations compared to 0 degrees inclination. When the toes are dorsiflexed in high heels, it stimulates the Windlass mechanism which in turn stiffens the plantar fascia and adducts the metatarsal heads, while the soft tissues shrink in response to loads.

Conclusion

High heels affected the shape of the transverse arch even in short term standing, and these effects increased as the height of the heel increased.

Use of Cine Loops and Structural Landmarks in Ultrasound Image Processing Improves Reliability and Reduces Error in the Assessment of Foot and Leg Muscles

OBJECTIVES

Foot and leg muscle strength and size are crucial to proper function. It is important to assess these characteristics reliably. Our primary objective was to compare the measurement of still images to cine loops. The secondary purpose was to determine interoperator and intraoperator reliability between operators of different experience levels using video clips and internal and external landmarks.

METHODS

Twelve healthy volunteers participated in our study. Internal (navicular tuberosity) and external (lateral leg length at 30% and 50% from the knee joint line) landmarks were used. Two operators each captured and later measured still and cine loop images of selected foot and leg muscles.

RESULTS

The 12 participants included 8 male and 4 female volunteers (mean age ± SD, 23.5 ± 1.9 years). Good to excellent intraoperator and interoperator reliability was seen (intraclass correlation coefficient range of 0.946-0.998). The use of cine loops improved the intraclass correlation coefficients for both intraoperator and interoperator reliability (0.5%-4% increases). The use of cine loops decreased the intraoperator standard error of the measurement and limits of agreement of the novice operator (decreases of 45%-73% and 24%-51%, respectively), and these became comparable to those of experienced operators using still images. The interoperator standard errors of the measurement dropped by 42% to 53%, whereas the limits of agreement dropped by 27% to 40%. No substantial changes were noted in the tibialis anterior across reliability metrics.

CONCLUSIONS

Improved protocols that take advantage of using internal bony landmarks and cine loops during both the image-gathering and measurement processes improve the reliability of research examining muscle size changes in the lower leg or foot associated with muscle changes due to exercise, injury, disuse, or disease.

A New Automatic Foot Arch Index Measurement Method Based on a Flexible Membrane Pressure Sensor

The foot arch index is an important index to evaluate the health of human feet and the biomechanics line, aiming at addressing the shortcomings of the low efficiency and slow speed of manual foot arch index measurement; in this work, an automatic foot arch index measurement method based on a flexible membrane pressure sensor was proposed. The distribution of plantar pressure data was obtained from the flexible membrane pressure sensor and converted into a digital image. The 8-neighborhood correlation pixel method was proposed to remove the interference of isolated noise points. In order to remove the toes’ data without affecting the foot sole data, the row element association algorithm was proposed. The front and back endpoints of the foot were automatically located to obtain the foot length, and the foot arch index was also automatically obtained based on the foot arch pressure area. Whether it was a high arch foot, flat foot or normal foot, the method proposed in this paper could accurately and quickly distinguish them. The prototype was developed, and its feasibility and validity were verified by a series of tests.

Developmental mechanisms underlying webbed foot morphological diversity in waterbirds

The webbed feet of waterbirds are morphologically diverse and classified into four types: the palmate foot, semipalmate foot, totipalmate foot, and lobate foot. To understand the developmental mechanisms underlying this morphological diversity, we conducted a series of comparative analyses. Ancestral state reconstruction based on phylogeny assumed that the lobate feet possessed by the common coot and little grebe arose independently, perhaps through distinct developmental mechanisms. Gremlin1, which encodes a bone morphogenetic protein (BMP) antagonist and inhibits interdigital cell death (ICD) in the foot plate of avian embryos, remained expressed in the interdigital tissues of webbed feet in the duck, common coot, little grebe, and great cormorant. Differences in Gremlin1 expression pattern and proliferating cell distribution pattern in the toe tissues of the common coot and little grebe support the convergent evolution of lobate feet. In the totipalmate-footed great cormorant, Gremlin1 was expressed in all interdigital tissues at St. 31, but its expression disappeared except along the toes by St. 33. The webbing of the cormorant's totipalmate foot and duck's palmate foot may have risen from distinct developmental mechanisms.

Does Function Determine the Structure? Changes in Flexor Hallucis Longus Muscle and the Associated Performance Related to Dance Modality: A Cross-Sectional Study

Background and Objectives: Flexor hallucis longus pathology is one of the most common conditions of the ankle and foot in dancers, due to the high demand of dance movements performed in an extreme plantar flexion and dorsiflexion range of motion. The objectives of this study were to determine the bilateral differences between the thickness and cross-sectional area of the flexor hallucis longus muscle in dancers, to establish possible differences between dance modalities, and to analyze whether there is a correlation between ultrasonographic parameters or performance variables and the dance modality. Material and Methods: A sample of 50 (29 classical and 21 contemporary) full-time pre-professional female dancers were included in the study. The thickness and cross-sectional area of the flexor hallucis longus muscle were evaluated for both limbs using ultrasound imaging. The range of movement of the first metatarsophalangeal joint was measured using functional extension with maximal ankle plantarflexion, balance was measured in a unilateral stance with the heel raised, endurance was evaluated through a modified heel rise fatigue test, and a counter movement jump to assess the vertical jump performance was measured bilaterally. Results: There were no significant differences recorded between the dominant and non-dominant limbs for each variable, within both groups. Contemporary dancers showed a greater thickness and cross-sectional area of the flexor hallucis longus muscle than classical dancers. However, classical dancers showed an increase of balance, endurance, range of movement of the first metatarsophalangeal joint, and counter movement jump with respect to contemporary dancers. Conclusion: Bilateral symmetry was identified in all variables for both groups. The size and performance of the flexor hallucis longus muscle may be influenced by the specific nature of dance modality.

Stiffness of the human foot and evolution of the transverse arch

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.

Relationships between Foot Morphology and Foot Muscle Strength in Healthy Adults

The purpose of this study was to investigate if measurements of foot morphology in sitting and standing positions can predict foot muscle strength. Twenty-six healthy male adults were recruited, and their foot morphology and foot muscle strength were measured. Foot morphological variables, toe flexor strength, and metatarsophalangeal joint flexor strength were measured by using a digital caliper, Ailitech-AFG500 dynameter and metatarsophalangeal joint flexor strength tester, respectively. Partial correlation and multivariate stepwise regression were used to explore the relationships between foot morphology and toe/metatarsophalangeal joint strength. Results adjusted by age and body mass index were as follows: (1) truncated foot length in sitting and standing positions and foot width in standing position were positively correlated with the flexor strength of the first toe; (2) foot length, foot width, and truncated foot length in both positions were positively related to the flexor strength of the other toes; (3) arch height index in sitting position and differences in navicular height were negatively associated with the flexor strength of the other toes; (4) differences in foot width were negatively associated with metatarsophalangeal joint flexor strength; and (5) the multivariate stepwise regression model showed that truncated foot length in sitting position, navicular height in standing position, differences in navicular height, foot width in sitting position, and differences in foot width were significantly correlated with toe/metatarsophalangeal joint flexor strength. Simple measurements of foot morphological characteristics can effectively predict foot muscle strength. Preliminary findings provided practical implications for the improvement of the foot ability by making specific foot muscle training sessions in professional sports and by compensating the predicted muscle strength defects to prevent foot injury.

A data-driven classification of 3D foot types by archetypal shapes based on landmarks

The taxonomy of foot shapes or other parts of the body is important, especially for design purposes. We propose a methodology based on archetypoid analysis (ADA) that overcomes the weaknesses of previous methodologies used to establish typologies. ADA is an objective, data-driven methodology that seeks extreme patterns, the archetypal profiles in the data. ADA also explains the data as percentages of the archetypal patterns, which makes this technique understandable and accessible even for non-experts. Clustering techniques are usually considered for establishing taxonomies, but we will show that finding the purest or most extreme patterns is more appropriate than using the central points returned by clustering techniques. We apply the methodology to an anthropometric database of 775 3D right foot scans representing the Spanish adult female and male population for footwear design. Each foot is described by a 5626 × 3 configuration matrix of landmarks. No multivariate features are used for establishing the taxonomy, but all the information gathered from the 3D scanning is employed. We use ADA for shapes described by landmarks. Women’s and men’s feet are analyzed separately. We have analyzed 3 archetypal feet for both men and women. These archetypal feet could not have been recovered using multivariate techniques.

Three-dimensional foot shape analysis in children: a pilot analysis using three-dimensional shape descriptors

BACKGROUND

Existing clinical measures to describe foot morphology are limited in that they are commonly two-dimensional, low in resolution and accuracy, and do not accurately represent the multi-planar and complex changes during development across childhood. Using three-dimensional (3D) scanner technology provides the opportunity to understand more about morphological changes throughout childhood with higher resolution and potentially more relevant 3D shape measures. This is important to advance the prevailing arguments about the typical development of children's feet and inform the development of appropriate clinical measures. 3D shape descriptors derived from 3D scanning can be used to quantify changes in shape at each point of the 3D surface. The aim of this study was to determine whether 3D shape descriptors derived from 3D scanning data can identify differences in foot morphology between children of different ages.

METHODS

Fifteen children were recruited from three age groups (2, 5, and 7 years of age). Both feet were scanned in bipedal stance, using the Artec Eva (Artec Group, Luxembourg, Luxembourg) hand-held scanner. Three dimensional shape descriptors were extracted from the 3D scans of the right foot, to create histograms for each age group and heat maps of representative participants for comparison.

RESULTS

There were changes to the dorsal, medial and lateral surfaces of the feet with age. The surfaces became less round along with an increase in indented areas. This is supported by the heat maps which demonstrated that the surfaces of the anatomical landmarks (e.g. the malleoli and navicular tuberosity) became more rounded and protruding, with indented surfaces appearing around these landmarks. On the plantar surface, the concavity of the midfoot was evident and this concavity extended into the midfoot from the medial aspect as age increased.

CONCLUSIONS

The findings of this study indicated that with increasing age the foot becomes thinner in 3D, with bony architecture emerging, and the medial longitudinal arch (MLA) increases in area and concavity. Three-dimensional shape descriptors have shown good potential for locating and quantifying changes in foot structure across childhood. Three-dimensional shape descriptor data will be beneficial for understanding more about foot development and quantifying changes over time.

Development of a quantitative measurement system for three-dimensional analysis of foot morphology using a smartphone

Existing techniques for measuring foot morphology are invasive or cumbersome. A new technique was developed using a smartphone, which can measure foot morphology to within 1 mm. This is shown to be applicable to the prediction of hallux valgus, which allows for early intervention.

Pilot Study of Cadence, a Novel Shoe for Patients with Foot Drop

Foot Drop is a mobility disorder that limits ankle dorsiflexion, complicating the swing phase of gait and balance. It is a common result of a neurological injury or disease such as stroke, cerebral palsy or multiple sclerosis. Here we present Cadence, a low-cost assistive shoe designed to passively improve the biomechanics and rhythmicity of gait for people with foot drop. The shoe reduces the magnitude of scuffing forces when dragging the foot forward across the ground by using regions of low-friction material that can retract into the shoe to restore friction during stance phase. We report the results from a pilot study of Cadence, which show the biomechanical and performance effects of the device for five adults with foot drop due to neurological disorder. In 3 of the 5 subjects, we found that the shoe immediately improved gait mechanics, speed over ground, and qualitative gait comfort.

Impact of footwear fitting on foot shape in primary schoolgirls

PURPOSE

The study aimed to analyze the footwear fitting and its impact on foot construction features in primary schoolgirls.

METHODS

The study group was comprised of 100 girls aged 9 years. The study relied on the CQ-ST podoscope and the Clevermess device for pertinent measurements. The data were analyzed based on the Mann-Whitney U-test, multiple regression analysis and simple regression.

RESULTS

Too short right footwear had 37% of the girls and the left - 38% of the girls, while too long shoes were worn respectively by: 14% of the girls and 15% of the girls. Too wide footwear in relation to the right foot width had 45% of the group and in relation to the left foot: 41% of the group. Too narrow right shoes had 23% of the group and the left - 32% of the group. Statistically significant influence of the excess of outdoor footwear width was found on the Clarke's angle values ( p = 0.041), the fifth toe setting of the right foot ( p = 0.015) and Wejsflog index of the left foot ( p = 0.036).

CONCLUSIONS

Most 9-year-old girls wear poorly fitted outdoor footwear. Appropriately selected footwear in terms of the width facilitates the formation of foot architecture, but wearing too wide footwear increases the risk of hollow feet and the varus deformity of the fifth toe.

[Ultrasound of the Foot (Adapted According to SGUM Guidelines)]

Ultrasound of the Foot (Adapted According to SGUM Guidelines) Abstract. This review paper explains the simplified ultrasound anatomy of the foot including the ankle, midfoot and the toes. The adapted basic standard planes are described in detail according to SGUM guidelines and illustrated with a selection of high-resolution ultrasound images. A profound knowledge of the sonographic anatomy is essential for the detection of pathologies.

Can skeletal surface area predict in vivo foot surface area?

The surface area of feet in contact with the ground is a key morphological feature that influences animal locomotion. Underfoot pressures (and consequently stresses experienced by the foot), as well as stability of an animal during locomotion, depend on the size and shape of this area. Here we tested whether the area of a skeletal foot could predict in vivo soft tissue foot surface area. Computed tomography scans of 29 extant tetrapods (covering mammals, reptiles, birds and amphibians) were used to produce models of both the soft tissues and the bones of their feet. Soft tissue models were oriented to a horizontal plane, and their outlines projected onto a surface to produce two-dimensional silhouettes. Silhouettes of skeletal models were generated either from bones in CT pose or with all autopodial bones aligned to the horizontal plane. Areas of these projections were calculated using alpha shapes (mathematical tight-fitting outline). Underfoot area of soft tissue was approximately 1.67 times that of skeletal tissue area (~ 2 times for manus, ~ 1.6 times for pes, if analysed separately). This relationship between skeletal foot area and soft tissue area, while variable in some of our study taxa, could provide information about the size of the organisms responsible for fossil trackways, suggest what size of tracks might be expected from potential trackmakers known only from skeletal remains, and aid in soft tissue reconstruction of skeletal remains for biomechanical modelling.

The Relationship Between Foot Feature Parameters and Postural Stability in Healthy Subjects

OBJECTIVE

Little has been explored about the disparate contribution of medial longitudinal arch (MLA) and lateral longitudinal arch (LLA) to human gait and postural stability. This study aims to investigate the correlation of foot feature parameters including both MLA and LLA with postural stability.

METHOD

Thirteen young and healthy subjects participated in this study. The newly developed FFMS extracted foot feature parameters in nonweight-bearing (NWB) and weight-bearing (WB) conditions along with postural stability parameters in single-leg-standing (SLS) condition. A bivariate correlation analysis was carried out to investigate the correlation between the foot characteristics and the postural stability parameters.

RESULTS

The foot length and width showed negative correlation with center of pressure (CoP) distance in medio-lateral (ML) and total direction, whereas the foot length in NWB and WB conditions, and the foot width in WB condition showed positive correlation with CoP distance in anterior-posterior (AP) direction. The height of the LLA curve and the area of the MLA were correlated with the postural stability parameters in AP direction. The ratios of the LLA height and area showed moderate correlation with the CoP distance in ML direction and total direction.

CONCLUSION

The size of a foot, such as the length and width, is correlated with postural stability. Whereas the MLA features are associated with postural stability in AP direction, the LLA features are associated with that in ML and total direction.

APPLICATION

The findings suggest that the roles and contributions of the MLA and LLA features in and to the postural control are different.