The crista terminalis is a vertical ridge of smooth myocardium within the right atrium of the heart. It is on the lateral wall of the chamber. It extends between the right side of the orifice of the superior vena cava inferiorly to the right side of the valve of the inferior vena cava. It marks the dividing line between the posterior, smooth sinus venarum - the remains of the developmental right horn of the sinus venosus - and the anterior, rough part of the right atrium - the original auricular chamber of the embryo. It forms from the superior part of the right venous valve where the sinus venosus enters the right atrium.
The sinuatrial node is within the upper part of the crista terminalis. On the external surface of the heart, the crista terminalis occasionally is represented as the sulcus terminalis.