Final answer:
The manubrium is the most superior section of the sternum, providing articulation points for the clavicles and the first ribs.
Step-by-step explanation:
The most superior section of the sternum is called the manubrium. The sternum, also known as the breastbone, is a major part of the anterior thoracic cage and is made up of three sections: the manubrium, body, and xiphoid process. The manubrium is the uppermost part, serving as an anchor for the clavicle and the first ribs through the sternoclavicular joint and costal cartilage respectively. The manubrium features the jugular notch and clavicular notches, which are palpable anatomical landmarks. The body of the sternum and the manubrium join at the sternal angle, a critical landmark for finding the second rib and counting the rest of the ribs.