Superior view. The Pulmonary artery (PA) arising from the right ventricle, which is separated from the left ventricle (LV) by the anterior descending artery (1). In the right inferior margin of the picture it can be observed the left atrium with its appendage (LAA). Observe how several anatomical variations of the left appendage hides (or not) the anterior descending artery and circumflex artery. Note also the complete absence of pulmonary “annulus”because this structure does not exists in the human pulmonary artery.