atrial orientation
Last reviewed 01/2018
The atrial myocytes are arranged in two layers; both are attached to the fibrous skeleton around the atrioventricular orifices:
- superficial layer:
- surrounds both atria
- merges with the interatrial septum
- deep layer:
- fibres do not extend to the opposite chamber, they only surround the atrium on their own side
- divided into two groups of fibres:
- arch-like: pass over the superior aspect of the chamber
- circular: pass around the circumference of the chamber; also surround the orifice of the auricles and the venae cavae