In Lead II, the positive electrode is positioned on which part of the body?

In Lead II of a standard 12-lead electrocardiogram, the positive electrode is placed on the left leg. This configuration allows for the optimal recording of the electrical activity of the heart as it represents the vector of depolarization moving from the right arm (negative electrode) to the left leg (positive electrode). This placement captures the heart's electrical signals as they move downwards and to the left, which is consistent with the typical orientation of the heart within the thoracic cavity.

The positioning of the electrodes is critical because it determines the view of the heart's electrical activity that is being measured, thus influencing the interpretation of the EKG results. By placing the positive electrode on the left leg, Lead II effectively reflects the depolarization wave front as it travels through the cardiac muscle, resulting in a clear and useful tracing for diagnosing various cardiac conditions.