See the Forest for the Trees
Jichao Zhao, PhD;
Robert S Stephenson, PhD (Liverpool John Moores University)
The heart has four chambers; two atria, and two ventricles. The left and right atrial appendages are pocket-shaped structures, which sit on top of the ventricles.
This image shows the structure of rabbit atrial appendages, which have been captured by a novel micro-computed-tomography (CT) technique.
At microscopic scale, the atrial appendage looks like a network - or forest - of highly interconnected cardiac muscle bundles.