  Before septation processes shape its four chambers, the embryonic heart is a
straight tube that spontaneously bends and twists breaking the left-right
symmetry. In particular, the heart tube is subjected to a cell remodelling
inducing ventral bending and dextral torsion during the c-looping phase. In
this work we propose a morphomechanical model for the torsion of the heart
tube, that behaves as a nonlinear elastic body. We hypothesize that this
spontaneous looping can be modeled as a mechanical instability due to
accumulation of residual stresses induced by the geometrical frustration of
tissue remodelling, which mimics the cellular rearrangement within the heart
tube. Thus, we perform a linear stability analysis of the resulting nonlinear
elastic boundary value problem to determine the onset of c-looping as a
function of the aspect ratios of the tube and of the internal remodelling rate.
We perform numerical simulations to study the fully nonlinear morphological
transition, showing that the soft tube develops a realistic self-contacting
looped shape in the physiological range of geometrical parameters.
