A positioning arm for positioning and holding a device within a
medical imaging environment
workspace has: (a) a free-end link in the form of a circular cylinder having a distal end face and an adjoining end face, with the adjoining end face forming a specified angle with the cylinder's centerline and the distal end face adapted to allow for the connection of the device to the free-end link, (b) a plurality of intermediate links, each in the form of a circular cylinder having end faces that form a specified angle with the links' centerline, and each of these intermediate links having a channel connecting their end faces, (c) a base link in the form of a circular cylinder having a base end face and an adjoining end face, with the adjoining end face forming a specified angle with the link's centerline and the base end face adapted to allow for the connection of the arm to a supporting surface, (d) a cable that passes through the link channels so that one cable end attaches to the free-end link and the other end attaches to the base link, and (e) a
locking mechanism that attaches to the cable and applies tension to the cable so as to pull adjoining end faces into contact so as to lock them together by frictional, wherein these components are fabricated from
MRI compatible materials (e.g., plastics, glass, ceramics, rubbers, composites, and certain non-
ferrous metals such as aluminum,
titanium,
brass, and nitilol).