The manubrium articulates with the clavicle medially.
Explanation:
The manubrium is seen as a <u>flat bone</u>at the <u>superior portion of the sternum</u>. It joins the clavicle medially, creating the sternoclavicular joint, by attaching to the <u>clavicular notch</u>. It is the strongest and thickest part of the sternum, which also <u>resembles a handle of a sword</u> (from Latin, <em>manus</em>, meaning <em>handle</em>). Inferior to the sternoclavicular joint, attachments for the first and second rib are present. The manubrium is also attached to the sternum via the sternomanubrial joint.