The crista terminalis (also known as the terminal crest, or crista terminalis of His) is a vertical ridge on the posterolateral inner surface of the adult

right atrium The atrium (; : atria) is one of the 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 mitral and tricuspid heart valves. ...

extending between 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 vei ...

, and 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 the ...

. The crista terminalis denotes where the junction of the embryologic

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

and the right atrium occurred during

embryonic development In developmental biology, animal embryonic development, also known as animal embryogenesis, is the developmental stage of an animal embryo. Embryonic development starts with the fertilization of an egg cell (ovum) by a sperm, sperm cell (spermat ...

. It forms a boundary between the rough trabecular portion and the smooth, sinus venosus-derived portion (sinus venarum) of the internal surface of the right atrium. The

sinoatrial node The sinoatrial node (also known as the sinuatrial node, SA node, sinus node or Keith–Flack node) is an ellipse, oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of Cell (biology), cells known as pa ...

is located within the crista terminalis.

Anatomy

The crista terminalis generally takes the form of a smooth-surfaced, crescent-shaped thickened portion of heart muscle at the opening into the right atrial appendage. It consists of fibromuscular tissue.

Features

On the external aspect of the right atrium, corresponding to the crista terminalis, is a groove - the terminal sulcus. The crista terminalis provides the origin for the pectinate muscles. The

is located in the superior part of the crista terminalis at the junction of the right atrium, and

Development

During the development of the human heart, the right horn and transverse portion of the

ultimately become incorporated with and form a part of the adult

. The right sinus horn of the sinus venosus develops into the sinus venarum; in the adult right atrium, the portion of right atrium derived from the sinus venosus has a smooth inner surface.

Clinical significance

A prominent crista terminalis may be mistaken for a cardiac mass during heart imaging; a prominent crista terminalis appears as a hyperechoic ridge on

echocardiography Echocardiography, also known as cardiac ultrasound, is the use of ultrasound to examine the heart. It is a type of medical imaging, using standard ultrasound or Doppler ultrasound. The visual image formed using this technique is called an ec ...

, and homogenous to adjacent atrial wall on CT and MRI.

References

External links