The left ~ventricle~ is the large lower cavity of the |heart|. Its walls are three times thicker than those of the right ~ventricle~, making it the most powerful chamber in the |heart|. Along with the three spiral layers shared by the right ~ventricle~ (the superficial spiral layer, the deep sinospiral layer, and the superficial bulbo layer), a fourth layer of muscle, the deep bulbo spiral layer, winds from the aortic and |mitral valve| rings around the left ~ventricle~ and back, making the ~ventricle~ stronger to withstand higher ~blood~ pressure. When the left ~ventricle~ contracts, the ~blood~ is pushed through the |aortic semilunar valve| and into the |aorta|.