Introduction to sternum or the breast bone
The sternum plays a very significant role in normal functioning of body. The sternum is connected to the rib by coastal cartilage to complete the ribcage circle. The ribcage circle thus formed protects the vital organs like heart, lungs and major blood vessels, from physical damage.
The fracture of the breastbone is called sternum fracture. The incidence of breastbone fracture is more common in females than in males. Sternum fracture is commonly noted in adults over the age of 50 years. Children are less prone to sternum fracture.
Sternum or breast bone fracture is noted in 5-8% of the individuals experiencing a trauma to the chest. It has been reported that about 60-90% of the sternum fractures occur due to motor accidents. The absence of airbags and failure to wear seatbelts are the most common reasons for sternum fracture in motor accidents. During a collision, the chest of the driver who is not wearing seat belt suddenly strikes the steering wheel or hits against the hard dashboard resulting in breast bone injury. The breastbone injury also can occur when the chest suddenly flexes. Other causes of sternum fracture can include occupational or sport related injuries. Research studies have shown that people who work in high rise construction sites and warehouses are at a risk of sternum fracture due to falls. People participating in sports such as wrestling, football, hockey, martial arts, weight lifting and boxing are also at risk of sustaining sternum fracture owing to falls or direct blows on the chest. The risk of sternum fracture due to falls or trauma can increase when the bone structure is weakened due to certain underlying disorders such as osteoporosis.
Signs and symptoms of sternum fracture
The signs and symptoms of breastbone fracture include the following:
- A crunching sound or grinding noise at the site of the injury.
- Bruising, tenderness and inflammation over the fracture or chest site.
- Pain in the chest region
- Breathing difficulty or pain in the chest when one coughs, laughs or sneezes
- Sudden contraction of the muscles (muscle spasm)
- Deformed appearance of the ribcage
Breastbone fractures associated with rib fractures can result in serious internal injuries to heart and lungs. The features of such cases are dependent upon the type of organ involved and the severity of the injury to the underlying organ.
Diagnosis of sternum fracture
The diagnosis of a breastbone fracture is generally arrived at based on the history of chest trauma, physical examination findings and imaging techniques. The doctor feels the breastbone to identify any changes in the shape or discontinuity in the structure. The chest region is also examined for deformations, bruising, or swelling. Plain X-rays of upper chest determine the severity and location of the sternal fracture. In case of severe injury, specialized imaging studies such as CT and MRI are done to detect any other associated injuries. The doctor particularly verify for the presence of internal injuries such as those to the lungs and the heart. Other additional tests may also be advised depending upon the suspected organ or structure injured.
Dangers of sternum fracture
Sternum fractures are mainly associated with the possibility of injuries to the heart and lungs. Other associated injuries that are noted to occur in individuals with fracture of the breast bone include damage to blood vessels in the chest, injury to the abdominal organs and vertebral fracture.
Breast bone fractures are also generally accompanied by rib fractures. The prevalence of death from sternum fracture associated injuries is estimated to be about 25-45%.
Since the ribcage and the sternum cover important organs like heart and lungs, chest injury can result in life threatening due to injuries such as punctured lungs or a ruptured aorta.
Injuries related with sternum fracture include: bruise to the heart (cardiac contusion), blood in the chest cavity (hemothorax), bruise in the lung (pulmonary contusion), aortic injury, rib fracture and, spinal cord injuries. Studies have shown that 10% of breastbone fractures are relatively associated with spinal fractures and about 20% are associated with rib fractures.
Other complications arising from breastbone fracture includes infection in bone (osteomyelitis), disease of the lung (pneumonia), and collapse of lung.
Breastbone fracture causes damage to the blood vessels or the ligaments around the ribcage in many instances. Incorrect healing or failure of bone fusion can result in deformity of bone. In some cases, the nonunion can compress the blood vessels or nerve cells leading to a condition referred to as thoracic outlet syndrome.
Sternum fracture treatment, prognosis and prevention
Sternum fracture treatment
The treatment of sternum fracture is dependent upon the severity of the fracture and the type of organ involved (if any). Life saving measures is initiated if severe or life threatening injuries to the lungs, heart or blood vessels are noted. In the absence of such injuries or, once condition of the affected individual is stabilized, other treatment measure are initiated.
The supportive treatment for sternum fractures includes rest to the injured areas for about 10-24 weeks. Applying cold compress to the injured region can help reduce the inflammation; however care should be taken not to apply pressure. Individuals suffering from sternal fractures are advised not to perform any actions such as lifting, carrying, or pushing heavy objects, and overhead work until it is healed. Medications to reduce pain and inflammation at the site of injury are also advised.
While the requirement of surgery in sternum fracture cases is quite low, they may be indicated when large fractures or involvement of underlying organs are reported.
Prognosis of sternum fracture
Breastbone fracture takes about 10 to 24 weeks for complete recovery. Chest pain is observed in this period. Nonunion of breastbone fracture is rarely seen.
Majority of sternum fracture are caused due to traffic collisions, so wearing seat belts can prevent breastbone fractures in such situations. Wearing protective equipments while involved in contact or high impact sports and while working at high rise construction sites can prevent the sternum fracture in these groups of individuals. Lifting, pulling heavy equipments at work without proper gears should be avoided.