title: Investigation of the mechanical behaviour of the foot skin.
abstract: OBJECTIVE
  The aim of this work was to provide computational tools for the characterization of the actual mechanical behaviour of foot skin, accounting for results from experimental testing and histological investigation. Such results show the typical features of skin mechanics, such as anisotropic configuration, almost incompressible behaviour, material and geometrical non linearity. The anisotropic behaviour is mainly determined by the distribution of collagen fibres along specific directions, usually identified as cleavage lines.
  
  
  METHODS
  To evaluate the biomechanical response of foot skin, a refined numerical model of the foot is developed. The overall mechanical behaviour of the skin is interpreted by a fibre-reinforced hyperelastic constitutive model and the orientation of the cleavage lines is implemented by a specific procedure. Numerical analyses that interpret typical loading conditions of the foot are performed. The influence of fibres orientation and distribution on skin mechanics is outlined also by a comparison with results using an isotropic scheme.
  
  
  RESULTS
  A specific constitutive formulation is provided to characterize the mechanical behaviour of foot skin. The formulation is applied within a numerical model of the foot to investigate the skin functionality during typical foot movements. Numerical analyses developed accounting for the actual anisotropic configuration of the skin show lower maximum principal stress fields than results from isotropic analyses.
  
  
  CONCLUSIONS
  The developed computational models provide reliable tools for the investigation of foot tissues functionality. Furthermore, the comparison between numerical results from anisotropic and isotropic models shows the optimal configuration of foot skin.
authors: Centre of Mechanics of Biological Materials, University of Padova, Padova, Italy.
authors: C G
authors: CG
authors: Fontanella
authors: E L
authors: EL
authors: Carniel
authors: A
authors: A
authors: Forestiero
authors: A N
authors: AN
authors: Natali
mesh_terms: D016880:Anisotropy; D019245:Compressive Strength / Q000502:physiology; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology*; D024022:Fibrillar Collagens; D005528:Foot / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D009068:Movement / Q000502:physiology*; D012879:Skin Physiological Phenomena; D013314:Stress, Mechanical; D013718:Tensile Strength / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*
chemical_list: D024022:Fibrillar Collagens
keywords: cleavage lines; constitutive formulation; finite element model; foot skin biomechanics; hyperelasticity