What connects the mitral valve leaflets to the papillary muscles?

The correct choice is the chordae tendinae, which are fibrous cords that play a crucial role in the function of the heart, specifically the mitral valve. These structures connect the mitral valve leaflets to the papillary muscles located in the ventricles of the heart.

During the contraction of the ventricles, the papillary muscles contract as well, which pulls on the chordae tendinae. This mechanism helps to keep the mitral valve leaflets closed and prevents them from prolapsing into the left atrium, thereby ensuring unidirectional blood flow from the left atrium to the left ventricle. The chordae tendinae thus serve as a vital support system for the valve, maintaining stability during the cardiac cycle.

The other options refer to structures that do not serve this specific function: the ligamentum arteriosus is a remnant of ductus arteriosus connecting the pulmonary artery and aorta, the septal wall separates the left and right heart chambers, and the annulus fibrosus is part of the fibrous skeleton of the heart that provides structural support for the heart valves, but does not connect the valve leaflets to the papillary muscles.