The right ventricle is the most anterior of the 4 heart chambers. It receives deoxygenated blood from the right atrium and pumps it into the pulmonary circulation. Blood enters the right ventricle through the atrioventricular orifice containing the tricuspid valve during diastole and in systole is ejected out through the pulmonary valve into the pulmonary trunk.
The right ventricle projects to the left of the right atrium and when viewed in the axial cardiac plane, is semilunar in shape wrapping around the anterolateral aspect of the left ventricle. It has thinner walls than the left ventricle due to lower right sided pressures compared to the left ventricle. It forms almost all of the anterior and inferior borders of the heart. It is separated from the left ventricle by the interventricular (IV) septum, which is concave in shape (i.e. bulges into the right ventricle). It has three walls named anterior, inferior, and septal.
The interior surface is thrown into irregular muscular ridges known as trabeculae carnae. A large prominent trabecula, the supraventricular crest separates the trabeculated part of the chamber from the smooth wall of the outflow tract. It acts to redirect blood approximately 140 degrees from the inflow tract to the outflow tract.
The inflow part of the ventricle receives blood from the right atrium via the tricuspid valve. The fibrous ring surrounding the valve forms part of the fibrous skeleton of the heart. Superiorly the chamber tapers as the funnel-shaped outflow tract, known as the conus arteriosus (or infundibulum), which lack trabeculae and continues beyond the pulmonary valve as the pulmonary trunk.
There are three papillary muscles that attach to the leaflets of the tricuspid valve:
- Anterior (largest) who’s chordae tendineae attach to the anterior and posterior cusps of the tricuspid valve
- posterior (smallest) who’s chordae tendineae attach to the posterior and septal cusps of the tricuspid valve
- septal who’s chordae tendineae attach to the anterior and septal cusps of the tricuspid valve
Arising from the apical aspect of the IV septum, the septomarginal trabecula (or moderator band) extends to the anterior papillary muscle and contains the right branch of the AV bundle.
- arterial supply
- predominantly from the right coronary artery and its branches
- conus artery supplies the infundibulum
- acute marginal arteries supply the anterior free wall
- posterior descending artery via septal branches supply the posterior 1/3 IV septum
- The other 2/3 of the IV septum is supplied by septal branches of the left anterior descending artery
- venous drainage
- middle cardiac vein and small cardiac vein drain into the coronary sinus