What are the components that form the sternoclavicular joint?

The correct choice identifies the components of the sternoclavicular joint, which is formed by the medial end of the clavicle and the manubrium of the sternum. This joint is a crucial structure in the shoulder complex, providing stability and allowing movements that facilitate arm elevation and rotation.

The manubrium is the upper part of the sternum and serves as the anchoring point for the clavicle, allowing for a broad range of motion in the shoulder girdle. The connectiveness between these two bones enables movements such as flexion, extension, and some degree of rotation at the sternoclavicular joint, contributing significantly to the overall mobility of the upper extremity.

In contrast, other combinations listed refer to joints or articulations that do not involve the sternoclavicular joint directly. The lateral end of the clavicle connects with the acromion of the scapula at the acromioclavicular joint, while the humerus articulates with the scapula at the shoulder joint, and the thoracic vertebrae relate to the ribcage but do not form a joint with the scapula. Understanding these relationships helps clarify the specific anatomy and function of the sternoclavicular joint in the context of upper extremity mechanics