Sternum

Siding the Sternum

-Fragments of manubrium and corpus sterni can be sided by noting that the anterior surface of this bone is rougher and more convex than the smooth, gently concave posterior surface. -The lines of fusion pass horizontally, and the mediolaterally widest point on the corpus sterni is at the third segment inferior to the manubrium.

Sternal Angle

Also called the manubriosternal joint is the angle formed, usually viewed laterally, between the fused manubrium and the corpus sterni.

Lines of Fusion

Often apparent between the sternebrae, these lines pass horizontally through the right and left costal notches for ribs 3-5.

Body

The central part, or body, of the sternum where ribs connect to complete the thoracic cage and fuses with the manubrium and xiphoid process.

Manubrium

The most massive, thickest, and squarest of three main sternal elements. It is the superiormost element of the sternum and is the widest part of this bone.

Xiphoid Process

The variably ossified inferior tip of the sternum. It often fuses with the corpus sterni in older adults. It shares the seventh costal notch with the body. This process can be partially ossified and may ossify into bizarre asymmetrical shapes with odd perforations. In short, the xiphoid is a highly variable element. The xiphoid process of the individual chosen to illustrate this text, for example, was not ossified at the time of death.

Coastal Notches

These occupy both sides of the manubrium inferior to the clavicular notches. These notches represent articulations with the costal cartilages of the first ribs. The manubrium shares articulation for the second ribs with the corpus sterni.

Clavical Notches

This occupys the superior corners of the sternum. It is here that the manubrium articulates with the right and left clavicles.

Jugular Notch

This the midline notch on the superior border of the manubrium.