The sternum is made up of three major parts: the manubrium, the body and the xiphoid process. The manubrium is the superior portion of the sternum.
The manubrium:
1. articulates with clavicles, R1, R2 and sternal body.
2. is generally found anterior to T3 and T4 vertebrae
3. is attachment for SCM & pec. major, sternohyoid, and sternothyroid muscles.
Tap on the manubrium in the image below and it will appear shaded red.