Cardiac apex

The cardiac apex is the pointed inferior end of the heart, formed mainly by the left ventricle. It lies toward the patient's left and supplies a useful endpoint for describing the cardiac long axis. The anterior interventricular sulcus and posterior interventricular sulcus approach this region along the ventricular surface.^[ref]

The cardiac apex is an anatomical landmark, not a fifth chamber or an opening through which blood leaves. Blood flow from the left ventricle passes through the aortic valve; a pointed chamber outline does not indicate the outlet. This distinction is helpful when translating a simplified heart-shaped drawing into actual chamber connections.

A concrete orientation exercise begins with an anterior view of a specimen: identify the cardiac apex, follow the anterior interventricular sulcus away from it, then locate the coronary sulcus. These landmarks relate the ventricular tip, ventricular boundary and atrial–ventricular boundary. Right and left refer to the patient's anatomy, so a frontal illustration viewed face-on reverses them relative to the viewer.

The distinction between a landmark and a measurement also matters for the apical impulse. A motion detected at the chest surface is an observation of transmitted movement, whereas the cardiac apex is a location on the heart. Similarly, an echocardiography image needs an identified viewing direction: distance from an image edge is not an anatomical definition of the apex. A shared anatomical reference makes different views comparable.