Septum primum (circle) and limbus (arrowhead) in a 2-day-old healthy foal visualized on a right parasternal oblique view obtained by rotating the ultrasound probe towards two o’clock and angulating dorso-caudally). CaVC: cranial vena cava, CrVC: cranial vena cava, LA: left atrium; RA: right atrium; RV: right ventricle.