Framework: The Sternum
The sternum has three parts: the manubrium, the body and the xiphoid process.
the manubrium - is connected to the collarbones and can be felt at the top of the chest. It also is connected to the first rib
the body of the sternum - the main breastbone which shields the organs of the torso, and is connected directly to ribs 2 - 7, and indirectly to ribs 8 - 10.
the xiphoid process - a thin, blade-like portion, at the bottom
The side view in the image above allows you to see the notches where the costal cartilages connect the ribs to the body of the sternum. You may be able to feel these bumps, where the bone and cartilage connect, by running a finger up and down the edge of your sternum.
cartilaginous connection allows the ribcase a degree of flexibility. In the
old "rib-reserve" theory of singing and speaking, the ribs were
held "up", and all the breathing was done abdominally. This lead
to very stiffly held ribcages, and sternii that were rigidly held in place.
In more recent developments of voice training, students are encouraged to
keep the sternum "soft", allowing the sternal joints to be as flexible,
and relaxed as possible.
The image at the right shows the sternum of an eleven year old - the bone of the sternum has yet to "ossify" completely. You can see how the bone develops from the centres of ossification and spreads outwards. These centres develop before the child is born, but don't completely ossify until the mid-teens. The sternal cartilages begin to ossify as the adult reaches older age as blood flow is very minimal.
Continue your exploration of the Skeleton:
Back to the Framework
More on the sternum...
More on the human sternum from Minnesota State University's e-Museum display on Skeletal anatomy.