10 Electro-medical apparatuses, namely, computers and display devices, calibration devices and replacement parts therefor, for medical purposes, namely, for neurosurgical, cranial, orthopedic, spinal, soft tissue, ear, nose and throat (ENT), plastic surgery, radiosurgical and robot-assisted applications; Medical navigation systems for use in locating and tracking the position of a patient and of instruments during image guided surgery, namely, high resolution computers, cameras, monitors, docking stations, headsets, probes, sensors, instrument adaptors, markers, target positioners and cables; Image guidance systems for medical purposes, namely, for neurosurgical, cranial, orthopedic, spinal, soft tissue, ear, nose and throat (ENT), plastic surgery, radiosurgical and robot-assisted applications, namely, system carts, each comprising a computer, mouse, keyboard, foot pedal, monitors, universal power supplies, system heads, each comprising light handles, light scanners, optical tracking systems and surgical luminaires