  The radial index of a 1-form on a singular set is a generalization of the
classical Poincar\'e-Hopf index. We consider different classes of closed
semi-analytic sets in R^n that contain 0 in their singular locus and we relate
the radial index of a 1-form at 0 on these sets to Poincar\'e-Hopf indices at 0
of vector fiels defined on R^n.
