  We propose the mechanism of spontaneous symmetry breaking of a bulk vector
field as a way to generate the selection of bulk dimensions invisible to the
standard model confined to the brane. By assigning a non-vanishing vacuum value
to the vector field, a direction is singled out in the bulk vacuum, thus
breaking the bulk Lorentz symmetry. We present the condition for induced
Lorentz symmetry on the brane, as phenomenologically required.
