What lead primarily measures forces moving from the head to the feet (inferiorly)?

What lead primarily measures forces moving from the head to the feet (inferiorly)?

image

1.Lead I
2.aVF
3.aVL
4.V1
5.V6

summary

Lead aVF places the positive electrode on the left foot. The negative electrode is the combination of the right and left arms. Leads II and III also measure this approximate direction of current.