What's the Difference Between a Concentric Needle and a Monopolar Electrode ?

When it comes to electromyography (EMG), you might hear about different types of electrodes. The concentric needle electrode and the monopolar electrode are two common examples, but they serve different purposes. A monopolar electrode is a single, insulated wire with an uninsulated tip. It's used in conjunction with a separate surface electrode placed on the skin, which acts as the reference. This setup records a broader area of electrical activity. In contrast, the concentric needle electrode integrates both the recording and reference points into a single device. The central wire records the signal, and the outer cannula provides the reference. This design allows for a much more localized and precise recording of a single motor unit, making it the preferred choice for detailed and specific diagnostic studies.