How many sets of electrodes are placed on the body in a 12-lead EKG?

In a standard 12-lead EKG, a total of 10 electrodes are used. This includes 6 limb leads—typically placed on the arms and legs—and 4 precordial (chest) leads, which are positioned on the chest. The limb leads measure the heart's electrical activity in the frontal plane, while the chest leads assess activity in the horizontal plane. The combination of these leads allows for a comprehensive view of the heart's electrical function from multiple angles, which is crucial for accurate diagnosis of various cardiac conditions. Thus, the correct answer reflects the actual number of electrodes used in this arrangement for a complete 12-lead EKG.