What are the Prominent muscular ridges that run along the inner surface of the auricle and across the adjacent atrial wall?

The prominent muscular ridges that run along the inner surface of the auricle and across the adjacent atrial wall are known as the pectinate muscles. These muscles are particularly well-developed in the right atrium, extending from the auricle into the main atrial cavity. They play a role in increasing the surface area of the atrium and are involved in the contraction of the atrial wall during the cardiac cycle.