The term "Stereotactic" is derived from the Greek words "Stereo" which means three-dimensional and "taxic" which refers to system or arrangement. "Tactus" is a Latin verb for touch.

Stereotactic neurosurgery refers to image-guided neurosurgery which offers the surgeon an accurate three-dimensional touch, so to speak. It is an invaluable tool in localisation. Broadly speaking, stereotactic neurosurgery employs either 'frame based' or 'frameless' techniques.

In frame-based stereotaxy, a stereotactic frame is fixed to the skull. With the aid of CT or MRI scans, this is used as a rigid co-ordinate system to localise any particular point in the patient's brain accurately. It allows the surgeon to perform surgery at an unseen target with precision.

In frameless systems, a computer-interface known commonly as a neuronavigation device is used to register a patients physical space to the corresponding images on the CT or MRI scans. This method of spatial localisation gives real-time feedback from the surgical field, providing a kind of 'road-map' which tells the surgeon where exactly he is operating in, anatomically speaking.