The sternum is a bone that lies in the anterior midline of the thorax and participates in forming the anterior part of the thoracic cage.

The sternum protects the thoracic organs from mechanical injury, provides attachment sites for various muscles, and also is the centre around which the superior ten ribs are directly or indirectly attached.

The sternum consists of three parts:

The lower border of the manubrium articulates with the superior border of the body at the site called the sternal angle.