A coupling and assembly for a cable routing system, the system having trough members with flanged ends. The coupling includes a U-shaped rib having a rail on an exterior surface of the rib. The coupling also includes a pivoting clamp pivotally coupled to the rib near a first end of the clamp so that the clamp may be pivoted between an open and a closed position. The clamp has a contoured clamping surface which is contoured to retain the flanged ends of adjacent troughs against the rail and the external surface of the rib when the pivoting clamp is in the closed position. The clamp also includes retention means which cooperate with retention means on the rib to releasably retain the clamp in its closed position.