The sternum is a long, flat bone situated centrally in the chest, forming the front boundary of the rib cage. Its primary function is to protect the heart, lungs, and major blood vessels from external force. A sternal fracture, or break in the breastbone, signifies that a substantial amount of force has been transmitted to the chest cavity. Because of the sternum’s protective role, a fracture is a serious injury requiring immediate medical evaluation to check for potential associated damage to underlying structures.
Identifying the Signs of a Sternal Fracture
The most recognizable indication of a sternal fracture is sudden, intense, and localized pain directly over the center of the chest following an impact event. This pain is often sharp and becomes significantly worse with any movement of the chest wall. Activities such as deep breathing, coughing, sneezing, or even laughing will typically exacerbate the discomfort due to the sternum’s continuous movement with the rib cage during respiration.
Secondary physical signs frequently include visible bruising (ecchymosis) and soft tissue swelling at the injury site. Tenderness upon light touch or palpation of the breastbone is a common finding. If the fracture is severely displaced, a palpable deformity or “step” in the bone’s surface may be detected.
Less common signs include crepitus, a crunching sensation caused by the broken bone ends rubbing together. Up to 20% of patients may also report difficulty breathing (dyspnea). This difficulty can be due to severe pain limiting lung expansion or may signal an underlying pulmonary complication.
Common Mechanisms of Injury
A sternal fracture is predominantly the result of significant blunt force trauma or a rapid deceleration injury. The force required to break the sternum is considerable, making motor vehicle collisions the most frequent cause, accounting for 60% to 90% of cases. In accidents, the injury often occurs when the chest impacts the steering wheel or dashboard, or when a seatbelt’s shoulder restraint concentrates force directly onto the breastbone during a sudden stop.
Though less common, other high-energy events can also lead to a sternal fracture, such as severe falls from heights or direct strikes during high-impact sports. Rarely, fractures can occur spontaneously in individuals with weakened bone density, such as those with osteoporosis or those on long-term steroid therapy. Fractures can also occur as a complication of cardiopulmonary resuscitation (CPR).
Immediate Steps and Emergency Protocol
The immediate and most important action following a suspected sternal fracture is to contact emergency medical services, such as 911, without delay. A sternal fracture is considered a marker of high-energy trauma, and the main danger is not the broken bone itself, but the possibility of associated, life-threatening internal injuries. The tremendous force needed to fracture the sternum can also damage the heart, lungs, and major vessels located directly behind it, potentially causing conditions like a myocardial contusion, pneumothorax, or aortic injury.
While awaiting medical professionals, individuals should be kept as still as possible to prevent further injury or displacement of fracture fragments. Avoid moving the person unless they are in immediate danger, and do not try to manipulate the injured area. Monitoring the patient’s breathing and level of consciousness is important, as changes should be communicated immediately to the emergency operator. Refrain from administering pain medication unless specifically instructed by a medical professional, as it can mask symptoms of internal bleeding or respiratory distress.
Clinical Diagnosis and Treatment
Upon arrival at a medical facility, the patient’s evaluation follows established trauma guidelines, beginning with an assessment of the airway, breathing, and circulation. Clinicians will perform a detailed physical examination, focusing on the location of pain and checking for any signs of instability or deformity in the chest wall. Diagnostic imaging is then used to confirm the fracture and assess for internal damage.
A lateral chest X-ray is often the initial imaging test, though the fracture is frequently difficult to see on standard frontal X-rays due to overlapping structures. A computed tomography (CT) scan is now considered the standard for high-impact trauma, providing superior sensitivity for detecting the fracture and identifying associated injuries to the lungs and heart. Cardiac monitoring (ECG) and blood tests for cardiac biomarkers, such as troponin, are routinely performed to rule out blunt cardiac injury.
The majority of isolated sternal fractures are treated conservatively with a focus on rest and pain management. Adequate pain control is important to ensure the patient can breathe deeply and cough, which helps prevent pulmonary complications like pneumonia or lung collapse. Most patients recover within 6 to 12 weeks, though pain can persist for up to three months. Surgery is reserved for rare cases involving severely displaced or unstable fractures, or when conservative management fails to resolve chronic pain or nonunion.