The sternum is formed by three bones; the manubrium, the sternal body and the xiphoid process (xiphisternum). These bones articulate together by hyaline cartilage with a fibro-cartilaginous disc to form the anterior and midline portion of the chest wall.
The has many articulations, where the manubrium articulates with the first rib and the clavicle while the sternal body articulates with the second to seventh ribs as well as the costal cartilages.
This CT scan was cropped from the file STS_036
The 3D model created from this scan can be reviewed at: