9.6: External Anatomy of the Heart

The fully developed heart in adults has an average weight ranging from 250 to 350 grams (9 to 12 ounces), with dimensions of approximately 12 cm (5 inches) in length, 8 cm (3.5 inches) in width, and 6 cm (2.5 inches) in thickness. In the context of well-trained athletes, the heart's size can be notably larger due to the exercise-induced addition of muscle proteins, enhancing its blood-pumping capacity. Nonetheless, it is vital to recognize that heart thickening does not always stem from exercise; it can also arise due to conditions like hypertrophic cardiomyopathy. This condition, characterized by abnormal heart thickening, poses a risk of sudden death in seemingly healthy young individuals.

Considering its shape, the heart boasts a broader area at its upper surface, termed the base, which gradually narrows as it extends to the apex, as depicted in Figure 5. The base aligns with the third costal cartilage level, while the apex is positioned between the fourth and fifth ribs.

The cardiac muscle receives nourishment from the right and left coronary arteries to sustain its function. These arteries branch into progressively smaller vessels, ultimately delivering oxygen-rich blood and essential nutrients to the myocardium.¹⁰

                           

Figure 5 | External Anatomy of the Heart | ¹¹ Anatomical representation of the human heart, showcasing key structures. The image includes two perspectives: (Left) an anterior view highlighting the right atrium and ventricle, the aorta, pulmonary artery, and the right coronary artery, and (Right) a posterior view displaying the left atrium and ventricle, the pulmonary veins, the coronary sinus, and the circumflex artery. The interventricular septum and the superior and inferior vena cava are also labeled.

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