Which structure forms the entire anterior wall of the right atrium?

Which structure forms the entire anterior wall of the right atrium?

• A. SA Node
• B. Coronary sinus ostium
• C. Fossa ovalis
• D. Right atrial appendage

Answer: (D)

The front wall of the right atrium is formed by the right atrial appendage, a muscular pouch that makes up the rough, anterior surface. This appendage contains the pectinated muscles and lines the anterior wall, contrasting with the smooth posterior wall derived from the sinus venosus. The fossa ovalis sits on the interatrial septum, not on the anterior wall. The SA node is located near the top of the crista terminalis and the coronary sinus ostium opens into the right atrium on the posterior wall near the inferior vena cava.

The front wall of the right atrium is formed by the right atrial appendage, a muscular pouch that makes up the rough, anterior surface. This appendage contains the pectinated muscles and lines the anterior wall, contrasting with the smooth posterior wall derived from the sinus venosus. The fossa ovalis sits on the interatrial septum, not on the anterior wall. The SA node is located near the top of the crista terminalis and the coronary sinus ostium opens into the right atrium on the posterior wall near the inferior vena cava.