Definition - “an action or stress resulting from applied forces which causes or tends to cause two contiguous internal parts of the body to deform in the transverse plane”.

Fast Facts

  • Increases when lateral movement occurs and also occurs when laying flat
  • When pressure load is constant and the shear forces increase the amount of tissue deformation may increase
  • Increased shear forces can exacerbate tissue damage
  • Shear inflicted ulcers often present with a less deep area swooping down to a deeper area with bruising a typical feature- skin edges may be ragged
  • Shear forces tend to cause deeper tissue damage which may not be immediately visible
  • Changes in position are likely to cause shear – for example when the head of bed is raised or lowered