  Recent experiments on monolayers of spindle-like cells plated on adhesive
stripe-shaped domains have provided a convincing demonstration that certain
types of collective phenomena in epithelia are well described by active nematic
hydrodynamics. While recovering some of the hallmark predictions of this
framework, however, these experiments have also revealed a number of unexpected
features that could be ascribed to the existence of chirality over length
scales larger than the typical size of a cell. In this article we elaborate on
the microscopic origin of chiral stresses in nematic cell monolayers and
investigate how chirality affects the motion of topological defects, as well as
the collective motion in stripe-shaped domains. We find that chirality
introduces a characteristic asymmetry in the collective cellular flow, from
which the ratio between chiral and non-chiral active stresses can be inferred
by particle-image-velocimetry measurements. Furthermore, we find that chirality
changes the nature of the spontaneous flow transition under confinement and
that, for specific anchoring conditions, the latter has the structure of an
imperfect pitchfork bifurcation.
