Organ
Heart
Connects the lung and body circulations
High-yield
The chamber nearest the sternum is mainly the right ventricle. The apex usually projects toward the left fifth intercostal space, but surface position depends on posture and individual anatomy.
Overview
The heart sits within the pericardium between the lungs. Its right side pumps toward the lungs, and its left side pumps toward the body. The left ventricle forms the apex; much of the posterior base belongs to the left atrium.
Reference facts
- Location
- Within the pericardial sac in the middle mediastinum, above the diaphragm
- Parts
- Two atria and two ventricles; left ventricular apex, mainly left atrial base and mainly right ventricular anterior surface
- Blood supply
- Right and left coronary arteries arising from the aortic root
- Innervation
- Autonomic fibers through cardiac plexuses modify rate, conduction and contraction
- Relations
- Sternum and costal cartilages anteriorly, esophagus posteriorly and diaphragm inferiorly
- Venous/Lymphatic drainage
- Most venous return reaches the right atrium through the coronary sinus; some veins open directly into chambers; lymph reaches mediastinal nodes
- Function
- Maintains pulmonary and systemic flow in series; right and left outputs balance over time in a normal closed circulation
Clinical correlation
An enlarged or shifted heart can change the position and character of the palpable impulse. That finding must be interpreted with body habitus and examination position rather than used alone to diagnose enlargement.
Frequently asked questions
Where is the heart located?
Within the pericardial sac in the middle mediastinum, above the diaphragm.
What does the heart do?
Maintains pulmonary and systemic flow in series; right and left outputs balance over time in a normal closed circulation.
What are the parts of the heart?
Two atria and two ventricles; left ventricular apex, mainly left atrial base and mainly right ventricular anterior surface.
What is the blood supply of the heart?
The heart is supplied by the right and left coronary arteries arising from the aortic root.