ECG Leads

Where is the RA electrode placed?     

On the right arm or just below the right clavicle.

Where is the LA electrode placed?     

On the left arm or just below the left clavicle.

Where is the RL electrode placed?      

On the right leg or right lower torso. It serves as the ground electrode. 

Where is the LL electrode placed?     

On the left leg or left lower torso.

Which limb electrode acts as the electrical ground?      

The right leg (RL) electrode. 

Do limb electrodes have to be attached to the wrists and ankles?           

No. They may be placed on the shoulders and lower torso if done symmetrically. 

Why should limb electrodes be placed symmetrically? 

To maintain accurate electrical measurements and reduce artifact.

What happens if the RA and LA electrodes are accidentally reversed?             

Lead I becomes inverted and the ECG may falsely suggest axis abnormalities. 

Which electrode does not directly contribute to ECG measurement?      

The RL (ground) electrode.   

Why is proper skin preparation important before electrode placement? 

It reduces impedance and improves signal quality.