We will see one by one the walls of the cardiac atrium, assimilating the latter to a cube. As such we consider 6 walls. To avoid the risk of losing ourselves, let us clarify: the upper face of the cube will be called a posterosuperior face, while the lower face is called anteroinferior face. The other faces come by themselves.
- Anterosuperior wall : corresponds to the sternocostal face of the heart .
- Anteroinferiore wall (or floor) : as stated in the introduction, it is the face at the bottom. In fact, it presents the right atrioventricular orifice , provided with a tricuspid valve.
- Posterior wall (or roof) : this is the upper face, facing upwards. Presents the outlet of the hollow veins. The inferior vena cava is provided with the eustachian valve.
- Posteroinferior wall : presents the outlet of the coronary sinus (a venous vessel that collects blood from the coronary circle, with the tebesio valve.
- Medial or septal wall : presents the oval fossa, or the remaining botallo orifice, an orifice that, in fetal life, directs blood to the left atrium.
- Lateral wall : introduces into the auricula, presents the combed muscles (for their typical comb shape), more evident in the right atrium
- Anterosuperior wall : also corresponds to the costal rib.
- Anteroinferior wall (or floor) : presents the left atrioventricular orifice, equipped with a bicuspid valve.
- Posterosuperior wall (or roof) : presents the outlet of the 4 pulmonary veins.
- Posterior inferior wall : corresponds to the diaphragmatic face of the heart.
- Medial wall : presents the semilunar fold, residue of the valve of the foramen ovale.
- Lateral wall : inserts into the auricula.