A sternal fracture, commonly referred to as a broken breastbone, is a break in the sternum, the long, flat bone located at the center of the chest. This injury results from a forceful impact that generates significant trauma to the front of the torso. Because the sternum shields the heart and lungs, its fracture indicates a high-impact event. A sternal fracture is considered a serious injury that necessitates prompt medical evaluation. Although the bone itself may heal well, the primary concern stems from the potential for associated injuries to the underlying organs.
Understanding the Sternum and How Fractures Occur
The sternum is a dagger-shaped bone that forms the central structure of the anterior rib cage. It is composed of three sections: the manubrium at the top, the body, and the small, cartilaginous xiphoid process at the bottom. The sternum connects with the collarbones and the first seven pairs of ribs via cartilage, providing essential structural support.
Fractures most frequently result from blunt force trauma to the chest wall, typically occurring in high-energy accidents. Motor vehicle collisions are the most common cause, accounting for 60% to 90% of all sternal fractures. The mechanism often involves rapid deceleration, such as a head-on crash, where the chest is thrown forward.
A specific and common cause is the impact against a locked shoulder seatbelt, sometimes referred to as “seatbelt syndrome.” As the body moves forward during a crash, the seatbelt restrains the torso, applying intense, concentrated force directly across the sternum. Direct impact from a steering wheel is another mechanism, often seen when an airbag fails to deploy.
Less common causes include significant falls, sports injuries, or direct blows to the chest. In elderly individuals with conditions like osteoporosis, a stress or insufficiency fracture can occur from less severe trauma or even spontaneously due to a pronounced forward curvature of the spine.
Key Symptoms of a Sternal Fracture
The primary symptom of a sternal fracture is sudden, sharp, and localized pain directly over the breastbone. This pain is often moderate to severe and is easily reproduced when the area is touched or pressed. The pain typically worsens significantly with movements that expand the chest wall, such as deep breathing, coughing, or sneezing. Pain can also be triggered by upper body movements, including bending forward, pushing, or pulling.
Tenderness and swelling are frequently present at the fracture site, and visible bruising (ecchymosis) may appear on the overlying skin. A concerning symptom requiring immediate attention is difficulty breathing (dyspnea), which occurs in up to 20% of cases. This shortness of breath may result from intense pain preventing full inhalation or signal an underlying injury to the lungs or heart. The inability to take deep breaths or cough effectively can lead to pulmonary complications like atelectasis or pneumonia.
Medical Confirmation and Assessing Associated Injuries
Diagnosis begins with a thorough physical examination, where a healthcare provider assesses the area for localized tenderness, swelling, and possible deformity. Confirming the fracture and ruling out internal damage requires medical imaging. Initial assessment often includes a chest X-ray, although a standard view has low sensitivity. A lateral chest X-ray is more effective for visualizing the fracture and bone fragment displacement.
Computed Tomography (CT) scanning of the chest is considered the definitive imaging modality. It provides a detailed, three-dimensional view of the sternum and surrounding structures, and is especially valuable for identifying associated injuries.
The most concerning aspect of a sternal fracture is the risk of concurrent injury to the organs immediately behind the breastbone, primarily the heart and lungs. As a result, a cardiac assessment is mandatory for nearly all patients. This assessment involves obtaining a 12-lead electrocardiogram (ECG) to check for abnormalities in heart rhythm or electrical conduction.
Blood tests are also used to measure cardiac enzyme levels, specifically cardiac troponin, a protein released when heart muscle is damaged. A rise in troponin or an abnormal ECG can indicate a blunt cardiac injury, such as a heart contusion. Patients with abnormal findings will require continuous cardiac monitoring and possibly an echocardiogram to check the heart’s function.
Treatment Approaches and Recovery Timeline
The management of a sternal fracture is primarily dictated by the stability of the fracture and whether any other internal injuries are present. The vast majority of isolated sternal fractures are treated non-operatively, meaning without surgery. The mainstay of this treatment is aggressive pain management using medications such as non-steroidal anti-inflammatory drugs (NSAIDs) or stronger prescription analgesics.
Adequate pain control is paramount because it allows the patient to breathe deeply and cough, preventing subsequent lung complications. Patients are advised to rest and limit activities that stress the chest, such as heavy lifting, pushing, or pulling, to allow the bone to heal naturally. Surgery is rare, typically reserved for fractures that are severely displaced, unstable, or those that fail to heal over time, a condition known as nonunion.
The recovery timeline for an isolated sternal fracture is generally favorable, with most patients experiencing an excellent prognosis. Significant chest pain usually begins to improve within six to eight weeks, and the bone typically takes about 10 to 12 weeks to achieve full healing.
Patients are advised to continue light activities but must avoid high-impact sports and strenuous upper-body exercises for at least two to three months. A full return to normal activities is usually possible within three months. Physical therapy may be recommended to address any stiffness in the shoulder or spine resulting from limited movement during recovery.