This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
In a standard Electrocardiogram, an augmented limb lead measures the electrical potential difference between 
Select and explain. 
A. Two limbs, B. One limb and two other limbs, C. One limb and neutral (Zero), D. Two limbs and two other limbs
B: One limb and two other limbs
Answer: B: One limb and two other limbs 
Explanation: Augmented limb leads are recordings between one limb and the other two limbs Augmented limb leads, designated by the letter a (aVR, aVL, aVF), are generally used Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:495 aVR: b/w right arm (+electrode)and left arm+left leg(-electrode) aVL: b/w the left arm(+electrodes) and right arm+left leg(-electrode) aVF: b/w the left foot (+electrode)and right arm+left arm(-electrode) Vector of augmented limb lead=3/2 vector of unaugmented limb lead.