5.1 Right Heart Anatomy Scope

Right Heart Anatomy Scope defines the comprehensive anatomical boundaries and components of the right heart, encompassing its internal and external structures relevant to cardiovascular anatomy and function. This scope includes detailed consideration of the right atrium, right ventricle, valvular apparatus, venous inflow pathways, and their spatial relationships within the thoracic cavity. It serves to delineate the morphological and functional aspects critical for understanding right heart physiology, pathology, and surgical or diagnostic interventions.

Right Atrial Internal Anatomy Inclusion

This section covers the internal features of the right atrium, including the morphology of the atrial chamber, the sinoatrial node region, atrial appendage characteristics, and the internal muscular architecture such as the pectinate muscles. It details the anatomical landmarks that define the atrial septal boundaries and venous inflow orifices.

Key structures included are:

• The sinus venarum, the smooth-walled posterior portion receiving systemic venous return.
• The crista terminalis, a muscular ridge demarcating the transition zone between the sinus venarum and the trabeculated anterior right atrial wall.
• The right atrial appendage with its trabeculated pectinate muscles.
• The openings of the superior vena cava, inferior vena cava, and coronary sinus.
• The location and histological features of the sinoatrial node.

Systemic Venous Entry Anatomy Inclusion

This section addresses the anatomy of systemic venous return into the right atrium, focusing on the superior vena cava (SVC), inferior vena cava (IVC), and coronary sinus. It includes the structural configuration and spatial orientation of these venous channels and their junctions with the right atrium.

Important elements:

• The SVC entrance superiorly, with its relation to the right atrial superior wall.
• The IVC orifice inferiorly, including the Eustachian valve and its clinical relevance.
• The coronary sinus ostium located posteroinferiorly in the right atrium and guarded by the Thebesian valve.
• The anatomical variations and their implications for hemodynamics and invasive procedures.

Right Atrioventricular Junction Inclusion

This segment covers the anatomical details of the right atrioventricular (AV) junction, the connection between the right atrium and right ventricle through the tricuspid valve apparatus.

Core components include:

• The annulus fibrosus forming the fibrous skeleton of the tricuspid valve.
• The three leaflets of the tricuspid valve (anterior, posterior, septal).
• The chordae tendineae attaching the leaflets to the papillary muscles.
• The anatomical disposition of the right AV orifice relative to the interventricular septum and conduction tissues.
• The region’s role in maintaining unidirectional blood flow and its structural changes in pathological states.

Right Ventricular Internal Anatomy Inclusion

This section describes the internal morphology of the right ventricle, emphasizing the chamber shape, trabeculations, and septal relationships.

Principal features are:

• The inlet, trabeculated apical, and outflow (conal) components of the right ventricle.
• The moderator band (septomarginal trabecula) which carries part of the right bundle branch.
• The arrangement of trabeculae carneae and their impact on ventricular contraction.
• The spatial relation to the interventricular septum and the right ventricular free wall thickness.

Right Ventricular Muscular Architecture Inclusion

This part elaborates on the muscular structure of the right ventricle, focusing on the organization of myocardial fibers and their orientation.

Details include:

• The layered arrangement of myocardial fibers contributing to right ventricular contraction mechanics.
• The relationship between the muscular architecture and the ventricular shape.
• The impact of muscular arrangement on ventricular compliance and ejection.
• The structural adaptations in physiological versus pathological states.

Right Ventricular Inflow Region Inclusion

This subsection concentrates on the anatomical features involved in the entry of blood from the right atrium into the right ventricle.

Key anatomical components:

• The tricuspid valve leaflets and their supporting apparatus.
• The right ventricular inlet area including the subvalvular apparatus.
• The spatial configuration relative to the atrioventricular node and conduction pathways.
• The anatomical and functional interface between the right atrium and right ventricle during diastole.

Right Ventricular Outflow Region Inclusion

This section addresses the anatomy of the right ventricular outflow tract (RVOT), which directs blood flow toward the pulmonary valve.

Included structures:

• The conus arteriosus or infundibulum, the smooth-walled superior section of the right ventricle.
• The relationship of the RVOT to the pulmonary valve and main pulmonary artery.
• The muscular and fibrous components that support and separate the RVOT from the left ventricular outflow tract.
• The anatomical landmarks important in congenital heart diseases and surgical approaches.

Pulmonary Root Transition Inclusion

This segment defines the anatomical transition zone between the right ventricular outflow tract and the pulmonary valve root.

Highlights:

• The pulmonary valve leaflets and annulus.
• The sinuses of the pulmonary valve and their spatial relationship to the pulmonary trunk.
• The fibrous support structures and their continuity with the right ventricular myocardium.
• The anatomical considerations for valve function and intervention.

Right-Sided Septal Landmarks Inclusion

This section includes the identification and description of septal landmarks visible from the right heart side.

Important structures:

• The membranous and muscular portions of the interventricular septum.
• The atrioventricular septum including the triangle of Koch and its clinical relevance.
• The septal leaflet of the tricuspid valve and its attachments.
• The position of conduction system elements relative to septal landmarks.

Detailed Septal Architecture Deferral

This section defers the intricate details of septal microarchitecture and histology to specialized branches, focusing here on macroscopic features only.

Detailed Tricuspid Valve Anatomy Deferral

Detailed anatomical and histological analysis of the tricuspid valve leaflets, chordae tendineae, and papillary muscles is deferred to specific detailed anatomical branches.

Detailed Pulmonary Valve Anatomy Deferral

In-depth description of the pulmonary valve leaflets, sinus structure, and related microanatomy is deferred to dedicated pulmonary valve anatomy content.

Right Heart Anatomy Boundary

Defines the anatomical limits of the right heart in relation to adjacent cardiac chambers and great vessels.

Boundaries include:

• Anterior boundary formed by the right ventricular free wall.
• Medial boundary shared with the interventricular septum.
• Superior boundary at the junction with great veins (SVC, IVC) and pulmonary artery.
• Posteriorly limited by the atrial septum and coronary sinus.
• Inferior boundary contiguous with diaphragmatic surface.