Sternal fractures are uncommon. They can be seen after car accidents with seatbelt or steering wheel chest injuries. Or after abrupt forward bending of the sternum (as might happen during a hard fall).

The sternum is a bone that is shaped like a man’s necktie, with a top portion called the manubrium (resembling the necktie “knot”). The most common place for the sternum to fracture is across the connection between the manubrium and the lower part of the sternum.

A severe fracture can cause the manubrium to lift forward, moving out of its normal position. This is called a “displaced” fracture. A displaced fracture usually requires surgical repair so that the bone sections can be pinned or wired back together.

By definition, a “hairline” fracture does not have displaced bone pieces. The only finding on an X-ray in a hairline fracture is a thin line resembling a strand of hair where the bone has developed a crack. A hairline fracture can be treated with pain medicine. And it does not require surgery — it will heal on its own.

A sternum “contusion” is simply a bruise of the bone, with pain but no fracture. It can also be treated with pain medicine and left to heal on its own.

It takes a pretty severe injury to fracture a sternum. So a sternal fracture should be of concern to doctors. Internal injuries to the heart or lungs may have happened at the same time. When a sternal fracture is diagnosed, it is reasonable for doctors to get a chest X-ray and an EKG (electrocardiogram). They can also use blood tests or ultrasound (echocardiogram) tests to check for heart or lung injury.

If the injury is very significant, doctors may advise hospitalization to monitor the heart for a short time.