Anatomy Flashcards
Regions of the right ventricle
The RV is composed of three anatomically distinct regions: the inlet, the trabecular apex, and the outlet
Description of the RV inlet
The inlet, or inflow tract, includes, and is limited by, the tricuspid valve. True to its name, the tricuspid is composed of three leaflets, the anterosuperior, inferior, and septal. These are tethered peripherally by fan shaped chordae tendinea, which are then anchored by the papillary muscles into the trabeculated myocardial wall, except for the cords of the septal leaflet,
which are directly attached to the interventricular septum via the
septal papillary muscle of Luschka
Description of the RV trabecular portion
The trabecular portion of the ventricle extends to the apex where the wall is particularly thin and prone to injury by cardiac catheters and pacing electrodes
Description of the RV outlet
The outlet, or outflow tract, is characterized by smooth, muscular walls. It is the only non trabeculated region of the RV, as both the inlet and apex contain numerous, coarse trabeculations. The outlet is composed of the smooth, muscular infundibulum, which divides the aorticopulmonary trunk. It extends from the base of the RV as a muscular sleeve that supports the leaflets of the pulmonary valve and surrounds and supports the base of the pulmonary trunk. Since the aorticopulmonary septum may be displaced in anomalous hearts, Anderson et al. proposed that the term infundibular septum be used to describe any structure that separates two semilunar valves.
What is the supraventricular crest
It is clasped by a prominent trabecula known as the septomarginal trabeculation. The supraventricular crest, or crista supraventricularis, is a muscular shelf that normally separates the tricuspid and pulmonary valves This structure often appears to be a bundle of muscle but is actually an infolding of the inner curve of the heart, known as the ventriculoinfundibular fold. This fold inserts into a prominent and important septal trabeculation, located toward the apex of the ventricle, known as the septomarginal trabeculation.
What is the septomarginal trabeculation
The septomarginal trabeculation (i the RV) is a prominent Y-shaped band that is continuous with the interventricular septum inferiorly and towards the base of the heart, gives rise to an anterosuperior limb and a posteroinferior limb The anterosuperior, or septal, limb migrates superiorly to overlie the outlet part of the muscular ventricular septum. Here, it supports the pulmonary valve in the outlet of the ventricle. The posteroinferior, or parietal, limb extends posteroinferiorly to the interventricular component of the membranous septum, reinforcing this muscular structure. The body of the septomarginal trabeculation continues down into the apex of the RV, breaking into several smaller, but prominent, trabeculations; most of these are termed simply “septoparietal bands”. One of these
trabeculations is particularly prominent: the moderator band. This band attaches to both the apex and base of the interventricular septum, then joins to support the anterior papillary muscle before crossing over to the free wall of the ventricle. Even in normal hearts, the moderator band is found in variable positions throughout the RV. The various septoparietal bands are also quite variable, especially in size, and some may appear large enough to be mistaken for the moderator band.
