Magnetically controlled linkage based devices

A magnetically controllable linkage based medical device for interventional medical procedures includes a magnetic tip subassembly including magnet elements thereon; a plurality of linkage body elements connected in sequence, a distal linkage body element coupled to the magnetic tip subassembly, wherein each linkage body element is configured for deflection in at least one deflection direction; a linkage base element coupled to a proximal linkage body element; a support body connected to the linkage base element; at least one pair of control wires passing to the magnetic tip subassembly; wherein the device is configured such that an externally-generated magnetic field deflects the magnetically-controlled linkage-based device in at least one deflection direction, and wherein selectively tensioning the control wires can hold the magnetically-controlled linkage-based device in a desired orientation. The device is configured such that the externally-generated magnetic field which deflects the magnetically-controlled linkage-based device is less than 40 millitesla.