The apex of the heart is formed by the inferolateral part of the left ventricle. It lies posterior to the left 5^th intercostal space in adults, usually approximately 9 cm (a hand’s breadth) from the median plane. It remains motionless throughout the cardiac cycle. It is where the sounds of mitral valve closure are maximal (apex beat); the apex underlies the site where the heartbeat may be auscultated on the thoracic wall.