What is the name of the muscular inner layer of the heart?

The muscular inner layer of the heart is referred to as the myocardium. This layer is primarily responsible for the heart's ability to contract and pump blood throughout the body. The myocardium is composed of specialized cardiac muscle tissue, which enables it to efficiently sustain powerful contractions and function continuously without fatigue. Its thickness varies in different chambers of the heart, being particularly thick in the left ventricle to accommodate the pressure needed to pump blood to the entire body.

In contrast, the endocardium is a thin layer lining the interior of the heart chambers and covers the heart valves, while the epicardium is the outer layer of the heart wall, also known as the visceral layer of the pericardium. The pericardium itself is the fibrous sac surrounding the heart that provides protection and lubrication. Understanding these distinct layers of the heart is vital for comprehending cardiac structure and function in the context of EKG interpretation and cardiovascular health.