Mechanics of heel-strike plantigrady in African apes.

The initiation of a walking step with a heel strike is a defining characteristic of humans and great apes but is rarely found in other mammals. Despite the considerable importance of heel strike to an understanding of human locomotor evolution, no one has explicitly tested the fundamental mechanical question of why great apes use a heel strike. In this report, we test two hypotheses (1) that heel strike is a function of hip protraction and/or knee extension and (2) that short-legged apes with a midfoot that dorsiflexes at heel lift and long digits for whom digitigrady is not an option use heel-strike plantigrady. This strategy increases hip translation while potentially moderating the cost of redirecting the center of mass ('collisional costs') during stance via rollover along the full foot from the heel to toes. We quantified hind limb kinematics and relative hip translation in ten species of primates, including lemurs, terrestrial and arboreal monkeys, chimpanzees, and gorillas. Chimpanzees and gorillas walked with relatively extended knees but only with moderately protracted hips or hind limbs, partially rejecting the first hypothesis. Nonetheless, chimpanzees attained relative hip translations comparable with those of digitigrade primates. Heel-strike plantigrady may be a natural result of a need for increased hip translations when forelimbs are relatively long and digitigrady is morphologically restricted. In addition, foot rollover from the heel to toe in large, short-legged apes may reduce energetic costs of redirecting the center of mass at the step-to-step transition as it appears to do in humans. Heel strike appears to have been an important mechanism for increasing hip translation, and possibly reducing energetic costs, in early hominins and was fundamental to the evolution of the modern human foot and human bipedalism.

The injection site in the tarsal tunnel to minimize neurovascular injury for heel pain: an anatomical study.

INTRODUCTION: The aim of this study was to investigate the location and distribution patterns of neurovascular structures and determine the effective injection point in the tarsal tunnel for heel pain. METHODS: Fifteen adult non-embalmed cadavers with a mean age of 71.5 years were studied. The most inferior point of the medial malleolus of the tibia (MM) and the tuberosity of the calcaneus (TC) were identified before dissection. A line connecting the MM and TC was used as a reference line. The reference point was expressed in absolute distance along the reference line using the MM as the starting point. For measurements using MRI, the depth from the skin was measured to inferior at an interval of 1 cm from the MM. RESULTS: The posterior tibial artery, lateral plantar nerve, and medial plantar nerve were located from 29.0 to 37.3% of the reference line from the MM. The distribution frequencies of the medial calcaneal nerve on the reference line from the MM were 0%, 8.60%, 37.15%, 37.15%, and 17.10%, respectively. The mean depth of the neurovascular structures was 0.3 cm. DISCUSSION: This study recommended an effective injection site from 45.0 to 80.0% of the reference line.

Foot Structure and Function in Habitually Barefoot and Shod Adolescents in Kenya.

Habitually barefoot (HB) children from the Kalenjin tribe of Kenya are known for their high physical activity levels. To date, there has been no comprehensive assessment of foot structure and function in these highly active and HB children/adolescents and link with overuse injuries. PURPOSE: The aim of this research is to assess foot structure, foot function, injury and physical activity levels in Kenyan children and adolescents who are HB compared with those who were habitually shod (HS). METHODS: Foot structure, function, injury prevalence, and physical activity levels were studied using two studies with equal numbers of HS and HB. HS and HB children and adolescents were matched for age, sex, and body mass. Foot arch characteristics, foot strength, and lower-limb injury prevalence were investigated in Study 1 (n = 76). Heel bone stiffness, Achilles tendon moment arm length and physical activity levels in Study 2 (n=62). Foot muscle strength was measured using a strength device TKK 3360 and heel bone stiffness by bone ultrasonometry. The moment arm length of the Achilles tendon was estimated from photographs and physical activity was assessed using questionnaires and accelerometers. RESULTS: Foot shortening strength was greater in HB (4.8 ± 1.9 kg vs 3.5 ± 1.8 kg, P < 0.01). Navicular drop was greater in HB (0.53 ± 0.32 cm vs 0.39 ± 0.19 cm, P < 0.05). Calcaneus stiffness index was greater (right 113.5 ± 17.1 vs 100.5 ± 116.8, P < 0.01 left 109.8 ± 15.7 vs 101.7 ± 18.7, P < 0.05) and Achilles tendon moment arm shorter in HB (right, 3.4 ± 0.4 vs 3.6 ± 0.4 cm, P < 0.05; left, 3.4 ± 0.5 vs 3.7 ± 0.4 cm, P < 0.01). Lower-limb injury prevalence was 8% in HB and 61% in HS. HB subjects spent more time engaged in moderate to vigorous physical activity (60 ± 26 min·d vs 31 ± 13 min·d; P < 0.001). CONCLUSIONS: Significant differences observed in foot parameters, injury prevalence and general foot health between HB and HS suggest that footwear conditions may impact on foot structure and function and general foot health. HB children and adolescents spent more time engaged in moderate to vigorous physical activity and less time sedentary than HS children and adolescents.

Anatomical and histological study to determine the border of sole skin.

PURPOSE: Transfer of a free skin graft from the submalleolar or plantar instep area to the palmoplantar area and finger defects is widely performed; however, the sites and the border of plantar skin have yet to be examined in detail. The aim of this study was to determine the border of sole skin. METHODS: Twelve paraformaldehyde-fixed cadavers were examined. Skin specimens were harvested from an area from the top of the medial malleolus extending to the top of the lateral malleolus of the right foot. The paraffin-embedded skin specimens were analyzed using histological (hematoxylin and eosin, Fontana-Masson, and elastica van Gieson stains) and immunohistochemical (cytokeratin 9) techniques. RESULTS: CK9-positive cells were present at the points between 21 and 78 % of the intermalleolar distance measured from the tops of the medial and lateral malleoli. The melanin index abruptly changed at the points 25 ± 7.1 and 75 ± 4.2 %. The skin thickness and amount of elastic fibers changed greatly at the points between 20 and 30 % and between 70 and 80 % of the intermalleolar distance. CONCLUSIONS: Submalleolar skin is quite different from sole skin. The border of sole skin lies at the points between 20 and 25 % of the intermalleolar distance from the medial malleolus, which macroscopically corresponds to the border of skin maceration. It would be better to use the submalleolar area for grafts for the dorsum of the fingers or toes, and the plantar instep area for the ventral areas of the fingers or toes.

The paratendineous tissues: an anatomical study of their role in the pathogenesis of tendinopathy.

The aim of this paper was to examine the macroscopic and microscopic characteristics of the paratendineous tissues (paratenon, epitenon and endotenon) of the calcaneal tendon to better understand their role in the pathogenesis of "tendinopathy". Ten non-embalmed legs from cadavers were used. Histological and immunohistochemical studies were done at the middle third of the tendon. Magnetic resonance images of the hind foot were made in 60 living subjects to analyze the morphological alterations of tendon and paratenon. The paratenon is a thick fibrous layer with few elastic fibers, continuous with the crural fascia, well vascularized and innervated. It forms a sheath around the tendon similar to a synovial layer, but less organized. Indeed, it has no complete epithelium, but only some cells producing hyaluronan, called fasciacytes. Crural fascia and paratenon can be clearly observed by MRI, appearing as homogeneous, low signal intensity bands, sharply defined in the context of subcutaneous tissue in T1-weighted sequences. The mean thickness of the crural fascia was 1.11 mm in healthy subjects and 1.30 mm in patients (p < 0.005). The mean value of paratenon thickness in patients was 1.34 mm, 0.85 in healthy (p < 0.0001). The paratenon is more highly vascularized and innervated than the tendon, supporting the hypothesis that it is the origin of pain in tendinopathy. The imaging study suggests that, an increase in the thickness of the paratenon more than 1.35 mm is predictive of paratendinopathy, even before tendon damage.

MRI of heel pain.

OBJECTIVE: The purpose of this article is to review the normal anatomy of the posterior ankle and hindfoot and review the causes of heel pain, with attention to the clinical, radio-graphic, and MRI findings. CONCLUSION: Heel pain is a common problem that may be due to a variety of soft-tissue and osseous abnormalities. Knowledge of the anatomy of the posterior ankle and hind-foot offers a useful way in approaching heel pain. Some of the more common causes include Achilles tendinosis, Haglund phenomenon, and plantar fasciitis. MRI offers superior soft-tissue contrast resolution and can be helpful in diagnosis as well as in presurgical planning.

Investigations on the viscoelastic behaviour of a human healthy heel pad: in vivo compression tests and numerical analysis.

The aim of this study was to investigate the viscoelastic behaviour of the human heel pad by comparing the stress-relaxation curves obtained from a compression device used on an in vivo heel pad with those obtained from a three-dimensional computer-based subject-specific heel pad model subjected to external compression. The three-dimensional model was based on the anatomy revealed by magnetic resonance imaging of a 31-year-old healthy female. The calcaneal fat pad tissue was described with a viscohyperelastic model, while a fibre-reinforced hyperelastic model was formulated for the skin. All numerical analyses were performed to interpret the mechanical response of heel tissues, with loading conditions and displacement rate in agreement with experimental tests. The heel tissues showed a non-linear, viscoelastic behaviour described by characteristic hysteretic curves, stress-relaxation and viscous recovery phenomena. The reliability of the investigations was validated by the interpretation of the mechanical response of heel tissues under the application of three pistons with diameter of 15, 20 and 40 mm, at the same displacement rate of about 1.7 mm/s. The maximum and minimum relative errors were found to be less than 0.95 and 0.064, respectively.

Reproducibility of sonographic measurement of thickness and echogenicity of the plantar fascia.

BACKGROUND: To evaluate the intra- and interrater reliability of ultrasonographic measurements of the thickness and echogenicity of the plantar fascia. METHODS: Eleven patients (20 feet), who complained of inferior heel pain, and 26 volunteers (52 feet) were enrolled. Two sonographers independently imaged the plantar fascia in both longitudinal and transverse planes. Volunteers were assessed twice to evaluate intrarater reliability. Quantitative evaluation of the echogenicity of the plantar fascia was performed by measuring the mean gray level of the region of interest using Digital Imaging and Communications in Medicine viewer software. RESULTS: Sonographic evaluation of the thickness of the plantar fascia showed high reliability. Sonographic evaluations of the presence or absence of hypoechoic change in the plantar fascia showed surprisingly low agreement. The reliability of gray-scale evaluations appears to be much better than subjective judgments in the evaluation of echogenicity. Transverse scanning did not show any advantage in sonographic evaluation of the plantar fascia. CONCLUSIONS: The reliability of sonographic examination of the thickness of the plantar fascia is high. Mean gray-level analysis of quantitative sonography can be used for the evaluation of echogenicity, which could reduce discrepancies in the interpretation of echogenicity by different sonographers. Longitudinal instead of transverse scanning is recommended for imaging the plantar fascia.

Three-dimensional morphology of heel fat pad: an in vivo computed tomography study.

Heel fat pad cushioning efficiency is the result of its structure, shape and thickness. However, while a number of studies have investigated heel fat pad (HFP) anatomy, structural behavior and material properties, no previous study has described its three-dimensional morphology in situ. The assessment of the healthy, unloaded, three-dimensional morphology of heel pad may contribute to deepen the understanding of its role and behavior during locomotion. It is the basis for the assessment of possible HFP morphological modifications due to changes in the amount or distribution of the loads normally sustained by the foot. It may also help in guiding the surgical reconstruction of the pad and in improving footwear design, as well as in developing a correct heel pad geometry for finite element models of the foot. Therefore the purpose of this study was to obtain a complete analysis of HFP three-dimensional morphology in situ. The right foot of nine healthy volunteers was scanned with computed tomography. A methodological approach that maximizes reliability and repeatability of the data was developed by building a device to lock the foot in a neutral position with respect to the scan planes during image acquisition. Scan data were used to reconstruct virtual three-dimensional models for both the calcaneus and HFP. A set of virtual coronal and axial sections were extracted from the three-dimensional model of each HFP and processed to extract a set of one- and two-dimensional morphometrical measurements for a detailed description of heel pad morphology. The tissue exhibited a consistent and sophisticated morphology that may reflect the biomechanics of the foot support. HFP was found to be have a crest on its anterior dorsal surface, flanges on the sides and posteriorly, and a thick portion that reached and covered the posterior surface of the calcaneus and the achilles tendon insertion. Its anterior internal portion was thinner and a lump of fat was consistently present in this region. Finally, HFP was found to be thicker in males than in females.

Variability of neural activation during walking in humans: short heels and big calves.

People come in different shapes and sizes. In particular, calf muscle size in humans varies considerably. One possible cause for the different shapes of calf muscles is the inherent difference in neural signals sent to these muscles during walking. In sedentary adults, the variability in neural control of the calf muscles was examined with muscle size, walking kinematics and limb morphometrics. Half the subjects walked while activating their medial gastrocnemius (MG) muscles more strongly than their lateral gastrocnemius (LG) muscles during most walking speeds ('MG-biased'). The other subjects walked while activating their MG and LG muscles nearly equally ('unbiased'). Those who walked with an MG-biased recruitment pattern also had thicker MG muscles and shorter heel lengths, or MG muscle moment arms, than unbiased walkers, but were similar in height, weight, lower limb length, foot length, and exhibited similar walking kinematics. The relatively less plastic skeletal system may drive calf muscle size and motor recruitment patterns of walking in humans.

Medial ankle and heel: ultrasound evaluation and sonographic appearances of conditions causing symptoms.

The complex anatomy of the medial ankle and hindfoot can make clinical assessment of medial ankle and heel pain challenging. Ultrasound is an accessible, relatively inexpensive modality, and modern high-resolution probes allow eloquent demonstration of the main structures that are implicated as potential causes of medial ankle pain. In this work we review highlights the clinically relevant anatomy and normal sonographic appearances of structures around the medial ankle and heel and discuss key techniques to allow optimal ultrasound assessment. The conditions that cause medial-sided ankle and heel symptoms are discussed with their characteristic sonographic appearances.

Automatic identification of gait events using an instrumented sock.

BACKGROUND: Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. METHODS: We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. RESULTS: Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. CONCLUSIONS: This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance.

Safe zone for the approach to the posterior sole (heel): a cadaver study.

BACKGROUND: Surgical approach to the posterior sole or heel is commonly used for various orthopedic procedures. The objective of this cadaver study was to identify the risks to local neurovascular structures using an approach to the posterior sole or heel and to define the safe zone for minimizing the risk of injury. METHODS: Eleven fresh-frozen cadaver limbs were used. A layered dissection was performed from skin to neurovascular structures. Distances of the entire foot length, the lateral plantar nerve from the heel, the calcaneocuboid joint from the heel, the nerve to abductor digiti minimi from the heel, and the lateral plantar nerve from the calcaneocuboid joint; and depth of the lateral plantar nerve from skin of sole in the midline, and angle of the lateral plantar nerve to the midline axis were measured. RESULTS: The mean entire foot length was 2,29.1 (range 215-250) mm. Location of the lateral plantar nerve from the heel in the dissecting midline axis was a mean of 93.5 (range 86-104) mm. Calcaneocuboid joint was located at a mean of 75.7 (range 70-85) mm from heel in the midline axis. The nerve to abductor digiti minimi was located at a mean of 48.1 (range 41-55) mm from the heel. Lateral plantar nerve was located at a mean of 19.4 (range 16-23) mm distal to the calcaneocuboid joint in the midline level. The angle at which the lateral plantar nerve crossed the dissecting midline incision was at a mean of 13.8° (range 9-20°). CONCLUSIONS: Based on these results, we defined the safe zone for the surgical approach to the posterior sole as anterior to the nerve to the abductor digiti minimi in the midline axis and posterior to the calcaneocuboid joint. There were no significant neurovascular structures observed in this zone.

Soft-tissue vibration and damping response to footwear changes across a wide range of anthropometrics in running.

Different factors were shown to alter the vibration characteristics of soft-tissue compartments during running. Changing pre-heel strike muscle activation or changing footwear conditions represents two possibilities to influence the vibration response via frequency shift or altered damping. Associated with the study of muscle pre-tuning is the difficulty in quantifying clean experimental data for the acceleration of soft-tissue compartments and muscle activities in heterogeneous populations. The purpose of this study was to determine the vibration and pre-tuning response to footwear across a wide range of participants during running and establish and describe groups formed according to the damping coefficient. 32 subjects were used for further analysis. The subjects ran at a self-selected speed (5 min) on a treadmill in two different shoes (soft & hard), while soft-tissue accelerations and muscle activation at the gastrocnemius medialis were quantified. Damping coefficients, total muscle intensity and dominant vibration frequencies were determined. Anthropometrics and skinfold measurements of the lower limbs were obtained. According to the damping coefficient response to the footwear intervention, three groups were formed, with most runners (n = 20) showing less damping in the hard shoe. Total muscle intensity, anthropometrics, and dominant vibration frequency across footwear were not different for these three groups. Most runners (84.4%) used the strategy of adjusting the damping coefficients significantly when switching footwear. Despite damping being the preferred adjustment to changes in footwear, muscle pre-tuning might not be the only mechanism to influence damping as previously suggested. Future studies should focus on the subject-specific composition of soft-tissue compartments to elucidate their contribution to vibrations.

Reliability testing of the heel marker in three-dimensional gait analysis.

INTRODUCTION: In three-dimensional gait analysis, anatomical axes are defined by and therefore sensitive to marker placement. Previous analysis of the Oxford Foot Model (OFM) has suggested that the axes of the hindfoot are most sensitive to marker placement on the posterior aspect of the heel. Since other multi-segment foot models also use a similar marker, it is important to find methods to place this as accurately as possible. The aim of this pilot study was to test two different 'jigs' (anatomical alignment devices) against eyeball marker placement to improve reliability of heel marker placement and calculation of hindfoot angles using the OFM. METHODS: Two jigs were designed using three-dimensional printing: a ratio caliper and heel mould. OFM kinematics were collected for ten healthy adults; intra-tester and inter-tester repeatability of hindfoot marker placement were assessed using both an experienced and inexperienced gait analyst for 5 clinically relevant variables. RESULTS: For 3 out of 5 variables the intra-tester and inter-tester variability was below 2 degrees for all methods of marker placement. The ratio caliper had the lowest intra-tester variability for the experienced gait analyst in all 5 variables and for the inexperienced gait analyst in 4 out of 5 variables. However for inter-tester variability, the ratio caliper was only lower than the eyeball method in 2 out of the 5 variables. The mould produced the worst results for 3 of the 5 variables, and was particularly prone to variability when assessing average hindfoot rotation, making it the least reliable method overall. CONCLUSIONS: The use of the ratio caliper may improve intra-tester variability, but does not seem superior to the eyeball method of marker placement for inter-tester variability. The use of a heel mould is discouraged.

Shorter heels are linked with greater elastic energy storage in the Achilles tendon.

Previous research suggests that the moment arm of the m. triceps surae tendon (i.e., Achilles tendon), is positively correlated with the energetic cost of running. This relationship is derived from a model which predicts that shorter ankle moment arms place larger loads on the Achilles tendon, which should result in a greater amount of elastic energy storage and return. However, previous research has not empirically tested this assumed relationship. We test this hypothesis using an inverse dynamics approach in human subjects (n = 24) at speeds ranging from walking to sprinting. The spring function of the Achilles tendon was evaluated using specific net work, a metric of mechanical energy production versus absorption at a limb joint. We also combined kinematic and morphological data to directly estimate tendon stress and elastic energy storage. We find that moment arm length significantly determines the spring-like behavior of the Achilles tendon, as well as estimates of mass-specific tendon stress and elastic energy storage at running and sprinting speeds. Our results provide support for the relationship between short Achilles tendon moment arms and increased elastic energy storage, providing an empirical mechanical rationale for previous studies demonstrating a relationship between calcaneal length and running economy. We also demonstrate that speed and kinematics moderate tendon performance, suggesting a complex relationship between lower limb geometry and foot strike pattern.

The biomechanics of heel ulcers.

Heel ulcers are common, dangerous and costly, but their etiology is poorly understood and no biomechanical studies were conducted to explore it. This paper describes a biomechanical investigation of heel ulcers using a theoretical model that characterizes the internal mechanical loading at the soft tissues of a supported heel. The study is aimed first at identifying some heel-ulcer-specific risk factors pointed out by the biomechanical theory, and second, at demonstrating the kind of support that biomechanical theory and computer modeling can offer in the conduct of clinical studies in the pressure ulcer field. The modeling demonstrated that atypical foot anatomies characterized by heavy-weight foot, sharp posterior calcaneus and thin soft tissue padding are theoretically more prone to heel ulcers. Diabetes and edema at the feet were also predicted to impose risks for heel ulcers, which agrees very well with clinical observations. This paper therefore demonstrated that a biomechanical theory can be used to explain and interpret clinical and epidemiological findings related to heel ulcers.

Effects of heel height with backpack loading in young people.

BACKGROUND: There are many intrinsic and extrinsic factors that could affect posture. Two of them are backpack and heel height. The aim of this study is to investigate the immediate static effects on cervical and lumbosacral postural changes to determine the effects of heel and forefoot heights with backpack loading on both vertebral curves and posture. METHODS: Craniovertebral (CVA), pelvic tilt (APT), and ankle joint motion angles were measured from sagittal photographs of 20 university students in a static posture while carrying backpacks. The same measurements were taken and recorded conventional shoes with heel and forefoot heights. Postural analysis software (PAS/SAPO) was used to conduct angle assessments of the photos. RESULTS: Postural angles of the vertebral column on the cervical and lumbosacral regions are changed immediately up to the posterior thoracic load with backpacks in young people. CVA was an average of 52° only shoes and no load condition, while the angle was reduced to 49° with loading. In contrast, an increasing angle with additional heel height and zero heel height in conventional shoes were reported. CVA increased with heights to 53° for the heel and 55° at the forefoot. The average APT angle was 14° only shoes and no load condition, and this angle increased to 18.9° with the 20% BW load. Accordingly for the no load and load conditions, the significant increase in the APT angle was 21° with the 20% BW load with heel height and 23° for the 20% BW load along with forefoot height. The heights provided negative effects on the vertebral posture and ankle angle. CONCLUSIONS: The results of the study indicate that it may not be advisable for young people to wear shoes with high heels and negative heel height by taking into account the risk factors in the body and ankle postural compensation while carrying a backpack.

Judging heel height: A new test for proprioception while standing reveals that young hypermobile children perform better than controls.

BACKGROUND: Children with Generalized Joint Hypermobility (GJH) have been reported to have poorer proprioception than children with normal mobility. However, they were usually tested under unloaded conditions and in an age-group in which pain starts to play a role. RESEARCH QUESTION: In contrast, some young children with GJH perform well in motor tasks, suggesting they may have good proprioceptive abilities if assessed more ecologically. METHODS: Children with GJH (Beighton score of  ≥ 5; mean age 8.34 years) were compared to children with a Beighton score of 4 or less. A proprioception test was performed using wedges of different heights to evaluate the ability to judge heel height. A pair of wedges of various heights, was placed under the children's feet at random and they were required to report the higher leg while standing RESULTS: Independent t-test showed that children with GJH performed better (p < 0.01) than controls, suggesting better proprioceptive abilities when assessed under loaded conditions SIGNIFICANCE: Children with GJH do not have inferior proprioception when tested under loaded conditions. The least one can say is that one should be careful in postulating that measuring passive position sense in one particular joint is necessarily the best estimation of proprioception. Body position during standing can be estimated on the basis of knowledge of joint positions (of the ankle in particular in the present test) but also of other information (loading of foot mechanoreceptors for example). In conclusion, the new test may be more suited to evaluate proprioception than the conventional tests, which rely on passive joint position estimation during sitting.

[Anatomical calcaneal external fixator self-designed according to the morphology of heel].

OBJECTIVE: The anatomical calcaneal external fixator was designed by measuring and calculating the morphological data of the heel. METHODS: A total of 100 normal people were randomly selected to obtain 200 hind foot data, including 45 males and 55 females, with an average age of 43.9 years (range, 19-67 years). According to the principles of human engineering and local anatomy, the morphological data of the heel in the weight-bearing standing position and supine position were measured with the direct measurement mode. The heel length, heel width, heel height, medial ankle height, lateral ankle height, and calcaneal pitch angle (CPA) were measured by vernier calipers and ulnar markers in weight-bearing standing position, and the gender groups and left and right foot groups were compared; the shape of the hind foot in the supine position was measured by three-dimensional (3D) dot matrix inverse model method. According to the stereoscopic data of the comprehensive anatomical morphology of the heel, the anatomical calcaneal external fixator was designed with AutoCAD 2019 and other 3D industrial design softwares. RESULTS: The measurements of shoe size, heel length, heel width, heel height, medial ankle height, lateral ankle height, and CPA in male were significantly higher than those in female ( P<0.05). There was no significant difference between the left and right feet in the other indexes except that the height of the medial malleolus of the left foot was significantly lower than that of the right foot ( t=-2.827, P=0.005). The measurement of 3D dot matrix inverse model in supine position showed that the heel part was non-circular arc edge, and many groups of arc edges fluctuate in a limited range. Based on the above data, an anatomical calcaneal external fixator was designed, which could fit the anatomic radian in theory, so as to be flexible in configuration. On this basis, the ordinary configuration, compression configuration, and orthodontic configuration were designed to meet the treatment needs of calcaneal fractures in different degrees. The ordinary configuration was suitable for patients with Sanders Ⅰ, ⅡA, and ⅡB calcaneal fractures with no or slight displacement of intra-articular fractures; the ordinary configuration was mainly used for simple fixing. The compression configuration was suitable for patients with Sanders ⅡC, ⅢA, and ⅢB, tongue fractures, and avulsion fractures with severe displacement of intra-articular fractures; the compression configuration used obliquely drawn console wires to fix the displaced bones. The orthodontic configuration was suitable for patients with Sanders ⅢC and Ⅳ calcaneal fractures with severe displacement of intra-articular fractures or severe calcaneal bone defects; the orthodontic configuration was a multi-module design, which took into account the stable fixation of the fracture and the arbitrary adjustment of the joint fixation angle. CONCLUSION: The hind foot is special for morphology, so the external fixator designed based on the vernier caliper measurement method and 3D dot matrix measuring plate measurement method is an anatomical type and its configuration can theoretically meet stable and flexible clinical needs.