The invention relates to an apparatus for orienting a surgical instrument, comprising: a tripod having a central socket； at least three legs emanating from the central socket of the tripod in the manner of a camera tripod, whereby the distance between tips of said first and second legs, and the distance between tips of said first and third legs, may be adjusted over a range of distances by adjusting the angles between said first and second legs and between said first and third legs, and a guide mountable on said tripod to define an orientation in space with respect to said reference plane relative to the tips of the tripod legs.
