Source:http://linkedlifedata.com/resource/umls/id/C0441908
NCI: A unipolar electrocardiogram lead site; the electrode is placed on the anterior chest wall at the fourth intercostal space (between ribs 4 and 5) to the left of the sternal border. In small animals it corresponds to V2-V3 where it is placed at the 6th left intercostal space near the sternum. In large animals it is placed over the 6th rib at the level of the costochondral junction on the left side of the thorax.,NCI: A unipolar electrocardiogram lead site; the electrode is placed on the anterior chest wall at the fourth intercostal space (between ribs 4 and 5) to the left of the sternal border. In small animals it corresponds to V2-V3 where it is placed at the 6th left intercostal space near the sternum. In large animals it is placed over the 6th rib at the level of the costochondral junction on the left side of the thorax.