A sternal fracture is a fracture

Bone fracture

A bone fracture is a medical condition in which there is a break in the continuity of the bone...

 of the sternum (the breastbone), located in the center of the chest

Chest

The chest is a part of the anatomy of humans and various other animals. It is sometimes referred to as the thorax or the bosom.-Chest anatomy - Humans and other hominids:...

. The injury, which occurs in 5–8% of people who experience significant blunt chest trauma

Chest trauma

Chest trauma is a serious injury of the chest. Thoracic trauma is a common cause of significant disability and mortality, the leading cause of death from physical trauma after head and spinal cord injury. Blunt thoracic injuries are the primary or a contributing cause of about a quarter of all...

, may occur in vehicle accidents, when the still-moving chest strikes a steering wheel or dashboard or is injured by a seatbelt. Sternal fracture can interfere with breathing by making it more painful; however, its primary significance is that it can indicate the presence of serious associated internal injuries, especially to the heart and lung

Lung

The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s.

Causes

Vehicle collisions

Car accident

A traffic collision, also known as a traffic accident, motor vehicle collision, motor vehicle accident, car accident, automobile accident, Road Traffic Collision or car crash, occurs when a vehicle collides with another vehicle, pedestrian, animal, road debris, or other stationary obstruction,...

 are the usual cause of sternal fracture; the injury is estimated to occur in about 3% of auto accidents. The chest of a driver who is not wearing a seat belt may strike the steering wheel, and the shoulder component of a seatbelt may injure the chest if it is worn without the lap component. It was common enough for the sternum to be injured by the seatbelt that it was included in the 'safety belt syndrome', a pattern of injuries caused by seat belt

Seat belt

A seat belt or seatbelt, sometimes called a safety belt, is a safety harness designed to secure the occupant of a vehicle against harmful movement that may result from a collision or a sudden stop...

s in vehicle accidents.

The injury can also occur when the chest suddenly flexes, in the absence of an impact.

Associated injuries

Because of the high frequency of associated injuries, clinicians are taught to suspect that a patient has multiple severe injuries if a sternal fracture is present. Sternal fracture is commonly associated with injuries to the heart and lungs; if a person is injured with enough force to fracture the sternum, injuries such as myocardial

Commotio cordis

Commotio cordis is a disruption of heart rhythm that occurs as a result of a blow to the area directly over the heart , at a critical time during the cycle of a heart beat. It is a form of ventricular fibrillation, not mechanical damage to the heart muscle or surrounding organs, and not the result...

 and pulmonary contusion

Pulmonary contusion

A pulmonary contusion is a contusion of the lung, caused by chest trauma. As a result of damage to capillaries, blood and other fluids accumulate in the lung tissue. The excess fluid interferes with gas exchange, potentially leading to inadequate oxygen levels...

s are likely. Other associated injuries that may occur include damage to blood vessel

Blood vessel

The blood vessels are the part of the circulatory system that transports blood throughout the body. There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and...

s in the chest, myocardial rupture

Myocardial rupture

Myocardial rupture is a laceration or tearing of the walls of the ventricles or atria of the heart, of the interatrial or interventricular septum, of the papillary muscles or chordae tendineae or of one of the valves of the heart...

, head

Head injury

Head injury refers to trauma of the head. This may or may not include injury to the brain. However, the terms traumatic brain injury and head injury are often used interchangeably in medical literature....

 and abdominal injuries

Blunt trauma

In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a body part, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma...

, flail chest

Flail chest

A flail chest is a life-threatening medical condition that occurs when a segment of the rib cage breaks under extreme stress and becomes detached from the rest of the chest wall. It occurs when multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall...

, and vertebral fracture. Sternal fractures may also accompany rib fractures and are high-energy enough injuries to cause bronchial tear

Tracheobronchial injury

Tracheobronchial injury is damage to the tracheobronchial tree . It can result from blunt or penetrating trauma to the neck or chest, inhalation of harmful fumes or smoke, or aspiration of liquids or objects.Though rare, TBI is a serious condition; it may cause obstruction of the airway with...

s (ruptures of the bronchiole

Bronchiole

The bronchioles or bronchioli are the first airway branches that no longer contain cartilage or glands in their submucosa. They are branches of the bronchi.The bronchioles terminate by entering the circular sacs called alveoli.- Structure :...

s). They may hinder breathing. Due to the associated injuries, the mortality rate

Mortality rate

Mortality rate is a measure of the number of deaths in a population, scaled to the size of that population, per unit time...

 for people with sternal fracture is high, at an estimated 25–45%. However, when sternal fractures occur in isolation, their outcome is very good.

There is controversy over the question of whether the presence of sternal fracture is an indication of cardiac injuries. Though over half of people with sternal fractures have been found to have electrocardiogram

Electrocardiogram

Electrocardiography is a transthoracic interpretation of the electrical activity of the heart over a period of time, as detected by electrodes attached to the outer surface of the skin and recorded by a device external to the body...

 and radionucleotide abnormalities (abnormal test results indicating cardiac dysfunction), blunt injury to the heart may not occur at a higher rate with sternal fractures than they do in other patients with multisystem trauma

Multiple organ dysfunction syndrome

Multiple organ dysfunction syndrome ', previously known as multiple organ failure or multisystem organ failure , is altered organ function in an acutely ill patient requiring medical intervention to achieve homeostasis...

.

Signs and symptoms

Signs and symptoms include crepitus

Crepitus

Crepitus is a medical term to describe the grating, crackling or popping sounds and sensations experienced under the skin and joints.-Causes:...

 (a crunching sound made when broken bone ends rub together), pain, tenderness

Tenderness (medicine)

In medicine, tenderness is pain or discomfort when an affected area is touched.Rebound tenderness is an indication of peritonitis....

, bruising

Bruise

A bruise, also called a contusion, is a type of relatively minor hematoma of tissue in which capillaries and sometimes venules are damaged by trauma, allowing blood to seep into the surrounding interstitial tissues. Bruises can involve capillaries at the level of skin, subcutaneous tissue, muscle,...

, and swelling over the fracture site. The fracture may visibly move when the person breathes, and it may be bent or deformed, potentially forming a "step" at the junction of the broken bone ends that is detectable by palpation

Palpation

Palpation is used as part of a physical examination in which an object is felt to determine its size, shape, firmness, or location...

. Associated injuries such as those to the heart may cause symptoms such as abnormalities seen on electrocardiograms.

The upper and middle parts of the sternum are those most likely to fracture, but most sternal fractures occur below the sternal angle

Sternal angle

The sternal angle or 'angle of Louis', from the Latin angulus Ludovici is the anterior angle formed by the junction of the manubrium and the body of the sternum in the form of a secondary cartilaginous joint . This is also called the manubriosternal joint or Angle of Louis...

.

Assessment and treatment

X-rays of the chest

Chest X-ray

In medicine, a chest radiograph, commonly called a chest X-ray , is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures...

 are taken in people with chest trauma and symptoms of sternal fractures, and these may be followed by CT scanning. Since X-rays taken from the front may miss the injury, they are taken from the side as well.

Management involves treating associated injuries; people with sternal fractures but no other injuries do not need to be hospitalized. However, because it is common for cardiac injuries to accompany sternal fracture, heart function is monitored with electrocardiogram. Fractures that are very painful or extremely out of place can be operated on to fix the bone fragments into place, but in most cases treatment consists mainly of reducing pain and limiting movement. The fracture may interfere with breathing, requiring tracheal intubation

Tracheal intubation

Tracheal intubation, usually simply referred to as intubation, is the placement of a flexible plastic or rubber tube into the trachea to maintain an open airway or to serve as a conduit through which to administer certain drugs...

 and mechanical ventilation

Mechanical ventilation

In medicine, mechanical ventilation is a method to mechanically assist or replace spontaneous breathing. This may involve a machine called a ventilator or the breathing may be assisted by a physician, respiratory therapist or other suitable person compressing a bag or set of bellows...

.

History

In 1864, E. Guilt published a handbook recording sternal fractures as a rare injury found in severe trauma. The injury became more common with the introduction and wide use of vehicles and the subsequent rise in traffic accidents. A rise in sternal fractures has also been seen with an increase in the frequency of laws requiring that seat belts be worn.