Where is the crista terminais located?

• A. On the posterior wall of the left atrium
• B. On the lateral wall of the RA
• C. In the right ventricle
• D. At the tricuspid valve

Answer: (B)

Crista terminalis is a prominent muscular ridge inside the right atrium that marks the boundary between the smooth posterior wall (sinus venarum) and the rough anterior wall with pectinate muscles. It runs along the lateral aspect of the right atrium, extending from near the opening of the superior vena cava down toward the inferior vena cava. This makes its location on the lateral wall of the right atrium the best answer. It is not located on the posterior wall of the left atrium, in the right ventricle, or at the tricuspid valve.