The heart is a powerful organ that works tirelessly to keep the body functioning. Many people wonder about its exact placement within the chest, often believing it to be entirely on the left side. Understanding its true position and the structures surrounding it provides a clearer picture.
Its True Position
The heart is located centrally within the chest cavity, nestled behind the breastbone, also known as the sternum. While often perceived as being on the left, it sits slightly to the left of the sternum, with a portion of its mass extending to that side. This muscular organ is situated between the two lungs, occupying a space called the mediastinum.
An adult heart is roughly the size of a clenched fist. Its broader upper part, the base, is positioned at the upper chest. The lower, pointed tip, the apex, is directed downward, forward, and to the left.
Why It Feels Left-Sided
The common sensation of the heart being on the left side of the chest stems from its unique orientation and the activity within its chambers. Although the heart is largely central, its apex points towards the left. This pointed tip is formed by the inferolateral part of the left ventricle.
The left ventricle is the largest and strongest chamber, responsible for pumping oxygen-rich blood to the entire body. Its powerful contractions create a noticeable impulse, often called the apex beat, which can be felt most prominently on the left side of the chest, around the fifth left intercostal space. This strong left-sided activity contributes significantly to the perception that the heart is located there.
Protection and Neighbors
The heart is well-protected within the chest by several surrounding structures. The rib cage, composed of the ribs and the sternum, forms a bony shield around the heart and lungs. This cage-like structure offers protection from external impacts.
Immediately surrounding the heart is a double-layered membrane called the pericardium, which acts like a sac, providing support and reducing friction as the heart beats. On either side, the heart is flanked by the lungs, with the left lung being slightly smaller to accommodate the heart’s position. Below the heart, the diaphragm, a large dome-shaped muscle, separates the chest cavity from the abdomen and supports the heart from underneath.