Left Atrium
The left atrium is the most posterior and superior of the 4 chambers. It is cuboidal in shape and smaller than the right atrium but its walls are more muscular. The 4 pulmonary veins drain into the posterior aspect of the left atrium.
Left Ventricle
The left ventricle is situated posterior to the right ventricle, and like its counterpart comprises an inlet portion, apical trabeculae, and an outlet portion. It is cone-shaped, more extensive and narrower than the right; it slopes from its base in the plane of the atrioventricular groove to the cardiac apex. It forms the apex of the normal heart.
Mitral Valve
The mitral valve, like the tricuspid valve can be divided into 5 components:
- Orrifice
- Annulus – Saddle shaped with dynamic shape change throughout the cardiac cycle.
- Leaflets – Bileaflet valve, anterior and posterior leaflets; each with 3 scallops.
- Chordae Tendinae – Primary and secondary chords.
- Papillary Muscles – Anterolateral & posteromedial.
Aortic Root & Valve
The aortic root is described as the centerpiece of the heart and refers to the location of the aortic valve between the LVOT and the ascending portion of the aorta. It is often portrayed as a unit consisting of many unique parts including; the sinuses of Valsalva, the annulus, the interleaflet trigones, aortic valve leaflets, commissures and sinotubular junction.
The aortic valve consists of three leaflets, the left coronary, right coronary & non coronary leaflets.