The terminal sulcus is a groove in the

right atrium The atrium ( la, ātrium, , entry hall) is one of two upper chambers in the heart that receives blood from the circulatory system. The blood in the atria is pumped into the heart ventricles through the atrioventricular valves. There are two at ...

of the

heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to t ...

. The terminal sulcus marks the separation of the right atrial

pectinate muscle The pectinate muscles (musculi pectinati) are parallel muscular ridges in the walls of the atria of the heart. Structure Behind the crest ( crista terminalis) of the right atrium the internal surface is smooth. Pectinate muscles make up the pa ...

s from the

sinus venarum The sinus venarum (also known as the sinus of the vena cava, or sinus venarum cavarum) is the portion of the right atrium in the adult human heart where the inner surface of the right atrium is smooth. The sinus venarum represents the portion of t ...

. The terminal sulcus extends from the front of the

superior vena cava The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein th ...

to the front of the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of th ...

, and represents the line of union of the

sinus venosus The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In mammals, it exists distinctly only in the embryonic heart, where it is found between the two venae cavae. However, the sinus v ...

of the embryo with the

primitive atrium The primitive atrium is a stage in the embryonic development of the human heart. It grows rapidly and partially encircles the bulbus cordis; the groove against which the bulbus cordis lies is the first indication of a division into right and left ...

. On the internal aspect of the right atrium, corresponding to the terminal sulcus is the

crista terminalis The crista terminalis or terminal crest represents the junction between the sinus venosus and the heart in the developing embryo. In the development of the human heart, the right horn and transverse portion of the sinus venosus ultimately become in ...

. The superior border of the terminal sulcus designates the transverse plane in which the

SA node The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximat ...

resides. The inferior border designates the transverse plane in which the

AV node The atrioventricular node or AV node electrically connects the heart's atria and ventricles to coordinate beating in the top of the heart; it is part of the electrical conduction system of the heart. The AV node lies at the lower back section of t ...

resides.

References

External links

Cardiac anatomy {{circulatory-stub