The sternum, commonly known as the breastbone, is a long, flat bone situated at the center of the chest. It serves as a protective shield for vital organs like the heart and lungs. A cracked sternum, or sternal fracture, is a break in this bone, almost always resulting from significant external force. Because of the high energy required to fracture it, a break in the breastbone is considered a serious injury demanding immediate medical attention.
Defining the Immediate Sensation: Localized Pain and Tenderness
The most immediate feeling of a fractured sternum is sharp, acute pain centered precisely over the breastbone. This pain is intense and constant, a deep ache that does not typically radiate to the arms or neck. The pain is highly localized to the fracture site, which becomes exquisitely tender.
Even slight direct pressure, or palpation, over the sternum dramatically increases discomfort. This localized tenderness indicates the bone has been damaged. While the pain is present at rest, it worsens considerably with any movement that engages the chest wall.
Functional Limitations and Associated Symptoms
The pain from a cracked sternum severely limits the functional capacity of the chest and torso. Deep breathing is agonizing, as chest wall expansion pulls on the muscles and ligaments attached to the fractured bone fragments. Simple, involuntary actions like coughing, sneezing, or laughing cause a spike in pain due to the sudden movement of the chest.
Patients often have difficulty rotating or bending their torso, as these movements can destabilize the fracture site. A distinct sensation of clicking, grinding, or popping, medically termed crepitus, may be felt over the breastbone, indicating broken bone fragments are rubbing together. Visible signs like bruising (ecchymosis) and swelling may accompany the injury, though these outward signs only appear in about half of all cases.
Common Mechanisms of Injury
A fractured sternum rarely results from a minor incident, as the bone is relatively thick. The injury almost always requires high-energy, blunt force trauma directed at the anterior chest wall.
Motor vehicle collisions are the most common cause, particularly when the chest strikes the steering wheel or is compressed by a seat belt during rapid deceleration. Other mechanisms include severe falls from a height or direct, forceful blows sustained during high-impact sports. The force involved in these injuries is often strong enough to cause damage to underlying structures.
What to Expect During the Healing Process
The sensation of a cracked sternum changes significantly as the body begins the repair process, which typically spans six to twelve weeks. Initially, the intense, sharp pain transitions to a more manageable, persistent dull ache. During the first few weeks, maintaining an upright posture is often more comfortable.
As the bone fragments start to knit together, a feeling of stiffness or tightness may develop across the chest wall. This sensation is normal and relates to the formation of new bone tissue, requiring adherence to modified activity levels. The tenderness and pain should gradually lessen over several weeks, but any sudden increase in pain or the return of a clicking sensation should prompt re-evaluation by a healthcare provider.