QS Study

Sulcus Terminalis

It is a groove on the lateral surface of the right atrium, running between the right side of the entrance of the superior vena cava & inferior vena cava. The terminal sulcus marks the separation of the right atrial pectinate muscles from the sinus venarum.

It corresponds with the crista terminalis inside the right atrium. At the junction between the right atrium, and the right auricle, on the outside of the heart, is the sulcus terminalis (a shallow groove).

Fig: Sulcus Terminalis of heart

Importance

It is an important demarcation between the embryonic atrium and sinus venosus. The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. The superior border of the terminal sulcus designates the transverse plane in which the SA node resides. The inferior border designates the transverse plane in which the AV node resides.

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