On a standard ECG, where is the ground lead placed?

On a standard ECG, where is the ground lead placed?

• A. Right leg
• B. Left leg
• C. Right arm
• D. Left arm

Answer: (A)

The ground lead serves as a quiet reference point and helps reduce electrical noise in the ECG recording. It is placed on the right leg to provide a stable, away-from-the-heart reference and to minimize interference, while not contributing to the measured signals. The other limb sites (left leg, right arm, left arm) are used for the limb leads that record heart activity, not as the grounding point. Placing the ground on the right leg keeps the signal clean and is the standard convention.

The ground lead serves as a quiet reference point and helps reduce electrical noise in the ECG recording. It is placed on the right leg to provide a stable, away-from-the-heart reference and to minimize interference, while not contributing to the measured signals. The other limb sites (left leg, right arm, left arm) are used for the limb leads that record heart activity, not as the grounding point. Placing the ground on the right leg keeps the signal clean and is the standard convention.