1. The distribution of terminals from vestibulospinal (VS) axons on the dendritic trees of neck motoneurons was determined by combining the anterograde transport of Phaseolus Vulgaris Leucoagglutinin (PHA-L) with intracellular staining techniques and three-dimensional reconstruction methods. 2. Contacts between VS axon terminals and dendrites were arranged in a nonuniform pattern that depended on the orientation (i.e., rostro-caudal vs. dorsolateral) of the dendrites. 3. This innervation pattern satisfies a critical structural condition necessary for selective nonlinear interactions between pairs of simultaneously active inputs to motoneurons.