Left ventricle
The structure and functionality of the left ventricle play a crucial role in the cardiovascular system. This section of the heart is distinguished by its conical shape, contributing significantly to the inferior surface of heart, left surface of heart, and notably forms the apex of the heart.
Compared to the right ventricle, the left ventricle is elongated and possesses a thicker myocardium layer, reflecting its critical role in pumping oxygenated blood throughout the body.
Left Ventricle Position
The left ventricle is situated anterior to the left atrium, with an orientation that places it partially behind and to the left of the right ventricle when viewed from the front.
This positioning means that much of the left ventricle is obscured by the right ventricle in an anterior view.
The interventricular septum forms the anterior wall and part of the right side of the left ventricle.
The left ventricle comprises several key areas: an Inlet of left ventricle, an outlet portion and a trabecular part
Inlet of left ventricle
The inlet portion is the area that contains the mitral valve apparatus
Aortic vestibule
The outlet portion sometimes called the aortic vestibule, is situated posterior to the right ventricle’s infundibulum, features smooth walls and serves as the outflow tract for the left ventricle.
The outlet of the left ventricle directly overlaps its inlet, creating a distinctive structural configuration where the exit path for blood precisely covers the entrance path
Trabecular part of left ventricle
Within the left ventricle, a complex network of thin muscle bundles can be seen, these are known as trabeculae carneae of left ventricle. They are primarily located in the ventricle’s apical third.
On its inner surface, the left ventricle houses two significant papillary muscles, identified as the superior papillary muscle of left ventricle and inferior papillary muscle of left ventricle.
Papillary muscles of left ventricle
These muscles, which are larger than their counterparts in the right ventricle, are situated below the commissures of the mitral valve and anchor the valve using strings known as chordae tendineae.
This arrangement ensures a balanced and efficient mechanism for valve operation, preventing valve prolapse and ensuring smooth blood flow from the left atrium to the left ventricle.
Superior (Anterior) papillary muscle of left ventricle
The anterior papillary muscle, also known as the superior papillary muscle of the left ventricle, is the most substantial of the two, has its origin on the lateral wall of the left ventricle, and attaches to the mitral valve through fibrous cords.
Inferior (Posterior) papillary muscle of left ventricle
The posterior or inferior papillary muscle, though smaller than its anterior counterpart, serves an equally important function. It emerges from the inferior wall of the left ventricle, also attaching to the mitral valve through fibrous cords.
Chordae tendinae of left atrioventricular valve
Chordae tendineae—fibrous cords connecting the mitral valve leaflets to the left ventricle. The chordae tendineae primarily link the valve to the papillary muscles, ensuring valve function during heart contractions.
Chordae tendinae spuriae of left ventricle
Interestingly, the left ventricle also contains false chordae tendineae, which are fibrous-muscular cords unattached to the atrioventricular valves.
Trabeculae carneae of left ventricle
Exploring the left ventricle’s distinct internal structure reveals similarities with the right ventricle, including the presence of raised muscular bands known as the trabeculae carneae. In the left ventricle, these bands are finer and more delicate compared to those in the right ventricle.
Interventricular septum
The interventricular septum is a critical structure positioned between the right ventricle and left ventricle of the heart. It features a distinctive curvature and consists of both a robust muscular section and a slender membranous section.
Muscular part of interventricular septum
The muscular section, which is substantial and constitutes the bulk of the septum, offering significant support and structure.
Membranous part of interventricular septum
The membranous section, is the thinner, upper segment of the septum.
Artrioventricular septum
Additionally, a third segment, termed the atrioventricular part, might be observed above the septal cusp of the tricuspid valve. This particular location, positions this part between the left ventricle and the right atrium, further underscoring the name, Atrioventricular septum, (Atrioventricular part of membranous septum)