Final answer:
The normal axis of the mean electrical axis in an ECG is situated in the bottom right quadrant, specifically between -30° and +90°, which is referred to as the normal quadrant.
Step-by-step explanation:
In the context of an electrocardiogram (ECG), the mean electrical axis refers to the average direction of the electrical impulses during depolarization of the ventricles. The normal axis for the mean electrical axis of the heart on an ECG falls between -30° and +90°. This places it in what is referred to as the normal quadrant, which is the bottom right quadrant if you were to imagine the axes on a graph. Therefore, when examining a normal ECG tracing, the mean electrical axis would typically be located in the normal quadrant of the frontal plane which encompasses the positive limb of Lead I and the positive limb of Lead II, indicating a normal pattern of cardiac depolarization.
An ECG is a critical tool in evaluating cardiac function and identifying abnormalities such as atrial fibrillation, ventricular tachycardia, and various degrees of heart block.