In monopolar CN VII stimulation, which way does the charge flow?

In monopolar CN VII (facial nerve) stimulation, the charge flow occurs from the anode to the cathode. This is fundamental to understanding the electrophysiological principles that govern nerve stimulation.

In monopolar configurations, a single stimulating electrode (the anode) is placed at the site of interest, while a return electrode (often referred to as the cathode in this context) is typically placed at a distant location, usually on the patient's body, such as the ground pad.

When stimulation is applied, the electrical current travels from the anode through the tissue and then enters the return electrode. The flow of charge from the anode to the cathode facilitates depolarization of the nerve fibers. The anode attracts the negatively charged ions, creating a potential difference that leads to the propagation of the nerve impulse.

Understanding the direction of charge flow is crucial for clinicians and technologists operating in intraoperative settings, as it influences the stimulation parameters and the overall response recorded during neurophysiological monitoring.