Epithelial tissues repair wounds through the collective movement of epithelial cells into the damaged area. This involves extension of the leading edge of cells, which exerts traction on the substrate to propel the cells forward, and the contraction of a supracellular actomyosin ring around the wound. Brugués et al. quantified the forces that cultured cells exert on substrates after laser-induced wounding. Consistent with forward movement, cells adjacent to the wound generated radial traction forces pointing away from the wound. Inward-pointing forces and tangential forces (parallel to the wound margin), which result from the transmission of contractile forces from the actomyosin ring to the substrate through focal adhesions, were also observed. Tangential forces could only be explained by the actomyosin ring being a heterogeneous structure, with some regions sustaining greater tension than others. Thus, alternate patterns of substrate compression and stretching drag the cell sheet into the wound area.