Cardiology Teaching Package
A Beginners Guide to Normal Heart Function, Sinus Rhythm & Common Cardiac Arrhythmias
Limb leads are made up of 4 leads placed on the extremities: left and right wrist; left and right ankle.
The lead connected to the right ankle is a neutral lead, like you would find in an electric plug. It is there to complete an electrical circuit and plays no role in the ECG itself.
Image: Position of Limb Leads