Sternocostal surface of heart is formed by –
**Core Concept**
The sternocostal surface of the heart is one of its two main surfaces, the other being the diaphragmatic surface. This surface is in contact with the sternum and the costal (rib) cartilages, which is why it is named as such.
**Why the Correct Answer is Right**
The sternocostal surface is formed by the anterior walls of the right ventricle and the left ventricle. The right ventricle contributes the majority of this surface, while the left ventricle contributes a smaller part. The surface is also covered by the epicardium, the outermost layer of the heart. The sternocostal surface is an important landmark for understanding the anatomy of the heart and its connections to the surrounding thoracic structures.
**Why Each Wrong Option is Incorrect**
* **Option A:** The base of the heart is formed by the atria and the great vessels, and is not related to the sternocostal surface.
* **Option B:** The apex of the heart is formed by the left ventricle, but it is not the sternocostal surface.
* **Option C:** The diaphragmatic surface of the heart is in contact with the diaphragm, not the sternum or costal cartilages.
**Clinical Pearl / High-Yield Fact**
The sternocostal surface of the heart is an important landmark for understanding the anatomy of the heart and its connections to the surrounding thoracic structures. It is also a common site for implanting pacemakers and other cardiac devices.
**Correct Answer:** C.