Reaction paths and classical and quantum trajectories are studied within a generalized Hamilton-Jacobi framework, which allows to put on equal footing topology and dynamics in chemical reactivity problems. In doing so, we show how high-dimensional problems could be dealt with by means of Caratheodory plots or how trajectory-based quantum-classical analyses reveal unexpected discrepancies. As a working model, we consider the reaction dynamics associated with a Muller-Brown potential energy surface, where we focus on the relationship between reaction paths and trajectories as well as on reaction probability calculations from classical and quantum trajectories. (C) 2009 Elsevier B.V. All rights reserved.