To know the anatomical location of the precordial leads V1-V6 and the limb leads I-III
Click to CompleteTo understand how the anatomical position of the ECG leads link in with relation
to the heart
To know which coronary arteries are associated with the specific ECG lead
territory
To understand the physiology of the limb leads and how they are
constructed
Chest electrodes:
V1 – 4th intercostal space – right sternal edge
V2 – 4th intercostal space – left sternal edge
V3 – 5th rib
V4 – 5th intercostal space – mid clavicular
V5 – anterior axillary line – 5th intercostal space
V6 – mid-axillary – 5th intercostal space
Limb electrodes:
LA – left arm
RA – right arm
LL – left leg
RL – right leg – neutral – not used in measurements
Leads I, II and III are called the limb leads
The electrodes that create these signals are located on the
limbs—one on each arm and one on the left leg
The limb leads form the points of what is known as Einthoven's triangle:
- Lead I is the voltage between the left arm (LA) electrode and right arm (RA) electrode
- Lead II is the voltage between the left leg (LL) electrode and the right arm
(RA) electrode
- Lead III is the voltage between the left leg (LL) electrode and the left arm
(LA) electrode
1. Limb Lead Reversals - Life in the Fast Lane
ECG Library [Internet]. LITFL: Life in the Fast Lane Medical Blog. 2011 [cited
2016 Apr 24]. Available from:
http://lifeinthefastlane.com/ecg-library/limb-lead-reversals/
2. Cardiac Monitoring [Internet]. LITFL: Life in the Fast Lane Medical Blog. 2010 [cited
2016 Apr 24]. Available from:
http://lifeinthefastlane.com/education/lead-positioning/
Images top to bottom:
1. http://nursingcrib.com/medical-laboratory-diagnostic-test/ecg-lead-placement/
2. http://www.sharinginhealth.ca/imaging/ECG_placement.html
3. Plymouth university medical school
4. Plymouth university medical school
5. http://www.passmedicine.com/
6. https://en.wikipedia.org/wiki/Electrocardiography