  The notions of stress and hyperstress are anchored in 3-dimensional continuum
mechanics. Within the framework of the 4-dimensional spacetime continuum,
stress and hyperstress translate into the energy-momentum and the hypermomentum
current, respectively. These currents describe the inertial properties of
classical matter fields in relativistic field theory. The hypermomentum current
can be split into spin, dilation, and shear current. We discuss the
conservation laws of momentum and hypermomentum and point out under which
conditions the momentum current becomes symmetric.
