Expansion
Fifth intercostal space in the mid-clavicular line
Expansion
- Normal position - fifth intercostal space, in the mid-clavicular line, about 9 cm from the midline
- It represents the point of maximal outward movement of the left ventricle
Displacement has two broad explanations:
- Cardiac enlargement - left ventricular dilatation displaces it down and out
- Mediastinal shift - a large effusion or tension pneumothorax pushes it away from the affected side, while fibrosis or collapse pulls it towards
The character matters as much as the position. A heaving, sustained apex suggests pressure overload such as aortic stenosis; a thrusting, displaced apex suggests volume overload such as mitral regurgitation; a tapping apex is a palpable first heart sound in mitral stenosis.