Cardiac anatomy from right to left

Left atrial appendage

The left atrial appendage is a finger like, trabecularized structure which originates supralaterally in the left atrium. It lies over the left atrioventricular groove, and partially covers the left coronary artery in it.
Its small, parallel-running muscles should not be mistaken for thrombus.

Axial and 3D-reconstructions illustrating the shape and location of the left atrial appendage (yellow arrows).