Heart in situ
After going through the study unit, you will be able to:
- Describe the location and orientation of the heart in situ.
- Identify the surrounding structures and their relationships with the heart.
- Name the vessels and nerves that comprise the neurovasculature surrounding the heart.
- Define the importance of the relationship between other structures and the heart.
The heart is often described as the central component of the cardiovascular system and muscular organ that pumps blood around the body with the pulmonary and systemic circulation. Studying the heart itself is important; exploring the anatomical relationships of the heart in situ however will allow you to better understand its function. This vital organ is located in the middle mediastinum, mostly to the left of the midsagittal plane and relates with the thymus and sternum (anteriorly), the lungs (laterally), the diaphragm (inferiorly), and the great vessels (posterosuperiorly).
The heart generally is the size of a fist and is positioned roughly along an axis extending from the right shoulder to the left hypochondrium. Its position has often been described as “a pyramid which has fallen over” where the apex is located on the left midclavicular line and points in an anterior-inferior direction. Its inferior surface, also known as the diaphragmatic surface, sits on the diaphragm and can be located at the level of the 5th-6th intercostal space. The superior border, lies at the level of the second costal space, while the posterior part, is located at the level of the third costal cartilage. It’s important to know where the heart is located and its orientation in clinical practice when listening for heart sounds with a stethoscope or while performing CPR in the case of an emergency.
Watch the following video to learn more about the heart in situ, its relationship with surrounding structures and how it depends on them to perform its function.
Take a quiz
To test yourself on what you’ve learned so far about the heart in situ, take the following quiz.
Did you find weak spots in your knowledge? Try out the customizable quiz below about the heart where you can decide exactly which topics you want to be tested on.
Take a closer look at the heart and its surrounding structures in the gallery below.
Location: Middle mediastinum, mostly to the left of the midsagittal plane
Orientation: Positioned in a direction extending from the right shoulder to left hypochondrium, with the apex biased towards the left
|Visceral relationships||Pericardium (sac surrounding the heart)
Arteries: Aortic arch, brachiocephalic trunk, right and left common carotid arteries, right and left subclavian arteries, internal thoracic artery, pericardiacophrenic artery, pulmonary trunk
Veins: Left and right internal jugular veins, left and right subclavian veins, left and right brachiocephalic veins, superior vena cava, pericardiacophrenic
Nerves: Left and right vagus nerves (CN X), left and right phrenic nerves