The sternum, commonly called the breastbone, is a long, flat bone that runs down the center of the chest. It is a three-part structure, consisting of the manubrium, the body, and the xiphoid process, and it connects to the ribs via cartilage to form the front of the rib cage. This central location gives the sternum a protective function, shielding the underlying heart, lungs, and major blood vessels within the chest cavity. A sternal fracture is a break or crack in this bone, an injury that is most often the result of significant force. Because of its protective role, a fracture warrants immediate medical attention.
Common Causes and Injury Mechanics
A sternal fracture results from direct, high-impact blunt trauma to the anterior chest wall. The most frequent cause is a motor vehicle collision, accounting for up to 90% of cases. This often occurs when a driver’s or passenger’s chest strikes the steering wheel or dashboard upon sudden deceleration. The rapid deceleration during a crash can also cause the shoulder harness of a seatbelt to exert immense pressure across the breastbone, leading to a specific type of injury sometimes termed a “seatbelt injury.” The force required to fracture this relatively strong bone is substantial, which is why associated internal injuries are a frequent concern. Other causes include severe falls from a height, direct blows during contact sports, or injury sustained during overly aggressive cardiopulmonary resuscitation (CPR).
Recognizing the Signs and Symptoms
Patients experience a sudden onset of severe, localized pain directly over the center of the chest. This pain is specific and easily reproduced with light pressure or touch. Discomfort is often intensified by movements that strain the chest, such as taking a deep breath, coughing, sneezing, or laughing. Pain can also be felt during certain upper body movements, including pushing, pulling, or lifting, due to the muscles attached to the sternum. Objective signs visible at the injury site include bruising and soft tissue swelling. In cases where the fracture is displaced, a palpable deformity, sometimes described as a “step,” or a crackling sensation known as crepitus, may be felt upon examination.
Diagnostic Procedures and Critical Associated Injuries
The initial evaluation for a suspected sternal fracture begins with a physical examination and a thorough history of the traumatic event. Imaging is then required to confirm the diagnosis, often starting with a lateral chest X-ray, which is useful for visualizing the break and any displacement in the bone. A Computed Tomography (CT) scan is the preferred imaging modality, especially in high-impact trauma. The CT scan provides detailed cross-sectional images for assessing fracture displacement and identifying injuries to underlying structures.
The primary concern with a sternal fracture is not the break in the bone itself, but the possibility of damage to the heart, lungs, and major blood vessels that the bone protects. It is estimated that up to two-thirds of patients with a sternal fracture have an associated injury.
A life-threatening complication is a myocardial contusion, essentially a bruise of the heart muscle, which can lead to abnormal heart rhythms. To evaluate this, patients undergo cardiac monitoring, including an electrocardiogram (ECG) and blood tests to check for elevated cardiac biomarkers, such as troponin. Pulmonary complications are also common and include pulmonary contusion, a bruising of the lung tissue, or a pneumothorax (collapsed lung). Injuries to the major blood vessels, such as aortic disruption, are less common but represent an immediate life-threatening concern.
Treatment Methods and Expected Recovery
The management of a sternal fracture is dictated by the presence and severity of any associated injuries. For patients with an isolated, non-displaced sternal fracture and no other complications, treatment is non-surgical and focuses on supportive care. Pain management is a central component, involving the use of analgesics to ensure the patient can breathe deeply and cough without excessive discomfort. Deep breathing exercises are actively encouraged to prevent pulmonary complications like pneumonia, which can occur if painful breathing leads to shallow ventilation and retained lung secretions. Rest and activity restriction are necessary to allow the bone to heal, and patients are advised to avoid heavy lifting or strenuous activity for several weeks.
For the rare cases of severely displaced fractures, significant instability, or failure of the bone to heal (non-union), surgical intervention may be required. This surgery, known as open reduction and internal fixation (ORIF), involves realigning the bone fragments and securing them with specialized plates or wires. The recovery period for an uncomplicated sternal fracture is generally positive, with pain improving substantially over six to eight weeks. Bony healing typically occurs within 10 to 12 weeks, and most patients can expect to return to their normal activities within a few months.