Comparative Functional Morphology of Human and Chimpanzee Feet Based on Three-Dimensional Finite Element Analysis

To comparatively investigate the morphological adaptation of the human foot for achieving robust and efficient bipedal locomotion, we develop three-dimensional finite element models of the human and chimpanzee feet. Foot bones and the outer surface of the foot are extracted from computer tomography images and meshed with tetrahedral elements. The ligaments and plantar fascia are represented by tension-only spring elements. The contacts between the bones and between the foot and ground are solved using frictionless and Coulomb friction contact algorithms, respectively. Physiologically realistic loading conditions of the feet during quiet bipedal standing are simulated. Our results indicate that the center of pressure (COP) is located more anteriorly in the human foot than in the chimpanzee foot, indicating a larger stability margin in bipedal posture in humans. Furthermore, the vertical free moment generated by the coupling motion of the calcaneus and tibia during axial loading is larger in the human foot, which can facilitate the compensation of the net yaw moment of the body around the COP during bipedal locomotion. Furthermore, the human foot can store elastic energy more effectively during axial loading for the effective generation of propulsive force in the late stance phase. This computational framework for a comparative investigation of the causal relationship among the morphology, kinematics, and kinetics of the foot may provide a better understanding regarding the functional significance of the morphological features of the human foot.

Estimation of an Individual Stature Using Foot, Foot Outlines and Footprint Measurements in Adult Saudi Population

Identification of an individual is considered one of the fundamental challenges for forensic scientists, especially from dismembered and mutilated body parts. To limit the pool of conceivable suspects in the forensic investigation process, footprints and foot outlines found at the crime scene are used to ease estimation of stature. The current study aimed to estimate individual stature using foot, foot outline and footprint measurements in a Saudi Arabian population. A descriptive cross-sectional study was carried out on two hundred healthy medical students from the Faculty of Medicine at the University of Tabuk in Saudi Arabia. Stature measurements and eight foot, foot outline and footprint measurements were taken from both sides. Saudi adult males were significantly taller than Saudi females. All measurement values were significantly higher in adult males than in adult females. Most measurements were considered to be positively correlated with stature in both sexes. Regression equations and multiple regression equations for stature determination from all measurements in both male and females on both sides were created. This study has demonstrated the reliability and utility of foot, foot outline and footprint measurements in stature estimation in a Saudi Arabian population that comparable standards developed from foot bones.

Analysis of Clinical Profiles, Deformities, and Plantar Pressure Patterns in Diabetic Foot Syndrome

Diabetic foot syndrome refers to heterogeneous clinical and biomechanical profiles, which render predictive models unsatisfactory. A valuable contribution may derive from identification and descriptive analysis of well-defined subgroups of patients. Clinics, biology, function, gait analysis, and plantar pressure variables were assessed in 78 patients with diabetes. In 15 of them, the 3D architecture of the foot bones was characterized by using weight-bearing CT. Patients were grouped by diabetes type (T1, T2), presence (DN) or absence (DNN) of neuropathy, and obesity. Glycated hemoglobin (HbA1c) and plantar lesions were monitored during a 48-month follow-up. Statistical analysis showed significant differences between the groups for at least one clinical (combined neuropathy score, disease duration, HbA1c), biological (age, BMI), functional (joint mobility, foot alignment), or biomechanical (regional peak pressure, pressure-time integral, cadence, velocity) variable. Twelve patients ulcerated during follow-up (22 lesions in total), distributed in all groups but not in the DNN T2 non-obese group. These showed biomechanical alterations, not always occurring at the site of lesion, and HbA1c and neuropathy scores higher than the expected range. Three of them, who also had weight-bearing CT analysis, showed >40% of architecture parameters outside the 95%CI. Appropriate grouping and profiling of patients based on multi-instrumental clinical and biomechanical analysis may help improve prediction modelling and management of diabetic foot syndrome.

New anatomical reference systems for the bones of the foot and ankle complex: definitions and exploitation on clinical conditions

Background A complete definition of anatomical reference systems (ARS) for all bones of the foot and ankle complex is lacking. Using a morphological approach, we propose new ARS for these bones with the aim of being highly repeatable, consistent among individuals, clinically interpretable, and also suited for a sound kinematic description. Methods Three specimens from healthy donors and three patients with flat feet were scanned in weight-bearing CT. The foot bones were segmented and ARS defined according to the proposed approach. To assess repeatability, intra class coefficients (ICC) were computed both intra- and inter-operator. Consistency was evaluated as the mean of the standard deviations of the ARS position and orientation, both within normal and flat feet. Clinical interpretability was evaluated by providing a quantification of the curvature variation in the medial-longitudinal and transverse arches and computing the Djiann-Annonier angle for normal and flat feet from these new ARS axes. To test the capability to also provide a sound description of the foot kinematics, the alignment between mean helical axes (MHA) and ARS axes was quantified. Results ICC was 0.99 both inter- and intra-operator. Rotational consistency was 4.7 ± 3.5 ° and 6.2 ± 4.4° for the normal and flat feet, respectively; translational consistency was 4.4 ± 4.0 mm and 5.4 ± 2.9 mm for the normal and flat feet, respectively. In both these cases, the consistency was better than what was achieved by using principal axes of inertia. Curvature variation in the arches were well described and the measurements of the Djiann-Annoier angles from both normal and flat feet matched corresponding clinical observations. The angle between tibio-talar MHA and ARS mediolateral axis in the talus was 12.3 ± 6.0, while the angle between talo-calcaneal MHA and ARS anteroposterior axis in the calcaneus was 17.2 ± 5.6, suggesting good capability to represent joint kinematics. Conclusions The proposed ARS definitions are robust and provide a solid base for the 3-dimensional description of posture and motion of the foot and ankle complex from medical imaging.

Comparative radiographic analysis of three-dimensional innate mobility of the foot bones under axial loading of humans and African great apes

The human foot is considered to be morphologically adapted for habitual bipedal locomotion. However, how the mobility and mechanical interaction of the human foot with the ground under a weight-bearing condition differ from those of African great apes is not well understood. We compared three-dimensional (3D) bone kinematics of cadaver feet under axial loading of humans and African great apes using a biplanar X-ray fluoroscopy system. The calcaneus was everted and the talus and tibia were internally rotated in the human foot, but such coupling motion was much smaller in the feet of African great apes, possibly due to the difference in morphology of the foot bones and articular surfaces. This study also found that the changes in the length of the longitudinal arch were larger in the human foot than in the feet of chimpanzees and gorillas, indicating that the human foot is more deformable, possibly to allow storage and release of the elastic energy during locomotion. The coupling motion of the calcaneus and the tibia, and the larger capacity to be flattened due to axial loading observed in the human foot are possibly morphological adaptations for habitual bipedal locomotion that has evolved in the human lineage.

Pseudotumor of the maxilla as first presentation of hemophilia B in a 1-year-old male

Pseudotumor is a rare complication of hemophilia with a prevalence 1–2% of all clinical cases. Commonly bone lesions affect long tubular bones, the pelvis, wrist and foot bones. According to world science literature only 16 cases of maxilla bone lesions in patients with hemophilia were found. This article describes a clinical case of maxilla pathological lesion with the destruction of facial skeleton bones in a one year old boy. The differential diagnosis included malignant and benign neoplasia, inflammatory processes. During laboratory examination a deficiency of IX coagulation factor was revealed and the patient was diagnosed with hemophilia В. The patient underwent surgical treatment by removing the lesion with specific replacement therapy; an intraosseous organizing hematoma was verified. The maxilla pseadotumor in this child was a manifestation of hemophilia. The patient's parents agreed to use the information, including the child's photo, in scientific research and publications.