This document discusses trajectory guides that include an instrument guide
with at least one lumen angled with respect to an orthogonal or other
through-axis. In one example, patterned lumens on the instrument guide
provide a mirror image pattern of trajectory axes intersecting a target
plane. In another example, height adjustment of the instrument guide
extends these or other targeting techniques to a three-dimensional
volume. This document also describes a method of manufacturing such an
instrument guide, which is also applicable to manufacturing an instrument
guide providing parallel lumens.