What is an Aortic Sinus?

An aortic sinus is one of three openings, or dilations, that occurs on the inner wall of the ascending aorta, also called the aortic root. Each sinus can also be called sinus of Valsalva, sinus of Morgangni, and Petit's sinus. The sinuses serve as critical pathways for the two coronary arteries, which allow proper function of the heart. These arteries supply blood to different parts of the heart, which pumps blood to the rest of the body.

The aortic sinuses are located in the ascending aorta. The three sinuses are situated in between each joining point of the aortic valve. Opposite the sinuses are the cusps of the aortic valve. The last aortic sinus ends at the sinotubular junction in the aortic root, where the aorta becomes a cylinder, or tube-like structure.

The aortic sinuses go by many names. Each of the three sinuses serves a unique purpose. Sinus of Valsalva, sinus of Morgangni, and Petit's sinus are all used to describe the same thing. These sinuses are named after different scientists or anatomists whose research brought more understanding of this part of the body. The three sinuses can be differentiated by their location.

The three sinuses are located side by side. From left to right, the first aortic sinus is the only one that is not connected to a coronary artery. For this reason, it is often referred to as the non-coronary sinus. It is located within the right posterior valve of the ascending aorta.

The next, or middle aortic sinus, is attached to the right coronary artery. The right coronary artery supplies blood to the bottom of the left ventricle, the back of the septum, as well as the right atrium and right ventricle. This sinus is located within the left posterior valve inside the aortic root.

Finally, the third and last aortic sinus is located at the far right of the line of aortic sinuses. It is attached to the left coronary artery. The left coronary artery divides into two separate branches. These branches include the circumflex artery and the left anterior descending artery. The circumflex artery supplies blood to the left ventricle and the papillary muscle. The left anterior descending artery supplies blood to the septum of the left ventricle.

Occasionally, problems can occur within the aortic sinus. One of these problems includes the possibility of a rupture, or aneurysm, in the sinus. Possible causes of this type of aneurysm include infective endocarditis on the inner wall of the aorta, as well as tertiary-stage syphilis.