The human heart is a four-chambered muscular pump that drives blood throughout the body. The two upper chambers, the atria, receive blood, while the two lower chambers, the ventricles, pump it out to the circulatory pathways. The right ventricle plays a unique role in the initial movement of blood. Understanding its location and structure clarifies how it manages its circulatory duties.
Anatomical Placement in the Thoracic Cavity
The right ventricle is situated within the chest, specifically in the central compartment of the thoracic cavity known as the mediastinum. It lies closest to the front of the body, directly behind the sternum and the adjoining costal cartilages. This anterior positioning makes the right ventricle the most prominent chamber when viewing the heart from the front, as it forms the majority of the heart’s anterior surface. The heart is tilted, which positions the right ventricle more anteriorly than the left-sided chambers.
This chamber extends from the right atrium near the base of the heart down toward the apex. In cross-section, the right ventricle has a characteristic crescent shape because it wraps around the much larger left ventricle. The muscular wall separating the two ventricles, the interventricular septum, bulges into the right ventricle’s space, contributing to its unique morphology.
Internal Structure and Associated Valves
The interior of the right ventricle is designed to handle the inflow and outflow of blood. Its muscular wall is significantly thinner than the left ventricle, measuring around 3 to 5 millimeters in thickness. This difference reflects the right side’s lower pressure workload. The inner lining of the chamber is characterized by a dense network of irregular muscular ridges called trabeculae carneae.
Two specialized valves control the direction of blood flow within the right ventricle.
Tricuspid Valve
The Tricuspid Valve is positioned between the right atrium and the right ventricle, regulating the blood entering the chamber. This valve is composed of three leaflets, or cusps, which open to allow blood in and seal shut to prevent backflow into the atrium during contraction.
Pulmonary Valve
The Pulmonary Valve is situated at the exit of the right ventricle, marking the beginning of the outflow tract. This semilunar valve has three cup-like cusps that ensure blood is propelled forward into the pulmonary circulation and does not flow back into the ventricle after contraction.
Role in the Pulmonary Circuit
The function of the right ventricle is to receive deoxygenated blood returning from the body and propel it into the pulmonary circulatory system. This process begins when the right atrium contracts, pushing blood through the open Tricuspid Valve into the relaxed right ventricle. Once filled, the right ventricle contracts, causing the Tricuspid Valve to snap shut and the internal pressure to rise. This pressure forces the blood through the open Pulmonary Valve and into the pulmonary trunk.
The pulmonary trunk divides into the right and left pulmonary arteries, which carry the blood to the lungs for gas exchange. There, the blood releases carbon dioxide and picks up oxygen before returning to the left side of the heart. The right ventricle’s circulation is termed the low-pressure circuit because the blood only travels a short distance to the lungs. This explains why the chamber’s muscular walls are comparatively thin; they do not require the force generation necessary for the left ventricle to pump blood throughout the body. The right ventricle must precisely match the output of the left side.