The heart is one of the most important organs in the human body. It is believed to be the first organ to become functional straight after conception. Normally, people tend to place the heart just above the left side of the chest in imagination, but in reality it is much closer to the midline. From the side, it occupies the space between the sternum and vertebrae, and anteriorly, it lies behind the sternum and directly above the diaphragm. When the diaphragm moves, the heart moves with it. The fact the heart is between this two bones (the sternum and vertebrae) enables blood to leave the heart even when it is not pumping thus ensuring the body tissues to get a continuous supply of blood.

 

    The heart is contained within a protective jacket of pericardium and the inside lined with a thin smooth membrane called endocadium. It is made up of four chambers: two atria and two ventricles. The left and right sides of the heart are separated by a thick interventricular / interatrial septum. From simplified diagrams of the heart, we tend to think that the atria lie above the ventricles, however, in reality they are actually behind the ventricles.

 

Image showing the position of the heart in the Human Body. Image courtesy of  https://upload.wikimedia.org/wikipedia/commons/6/6b/Surface_anatomy_of_the_heart.png