A three dimensional morphologically realistic model of atrial propagation is developed, based on the male Visible Human dataset and the Fitzhugh-Nagumo equations for cardiac excitation. The atrial shell geometry incorporates eleven different anatomical structures, including the pulmonary veins, and the septum, Bachmann's bundle and coronary sinus as interatrial conduction pathways. Although the model utilizes a simplified cellular model of cardiac excitation it is able to reproduce a variety of electrophysiological phenomena including: autorhythmicity of the sinoatrial node and its ability to excite surrounding atrial tissue, spiral re-entrant wavefronts, ectopic beats originating in the PV and their termination by circumferential ablation of the PV. The model is an important tool to quantitatively study atrial excitation under normal conditions and during atrial fibrillation.