The seatbelt kept you in your seat. The airbag may have deployed. And now, hours later, the center of your chest hurts in a way that was not there at the scene.

Sternum pain after a car accident is one of the most frequently reported — and most frequently dismissed — post-crash complaints. Patients describe it as a deep ache, a sharp pain when breathing, or a tenderness that makes it feel like something is bruised right down the middle of the chest. In many cases, that is exactly what has happened. And in some cases, it is more.

The sternum, or breastbone, is positioned directly in the path of the seatbelt, the steering wheel, and the force of an airbag deployment. When a crash happens, any or all of those forces can be enough to bruise or fracture it — and the tricky part is that you cannot tell which by pain level alone.

This article explains what causes sternum pain after a crash, what symptoms should concern you, why the pain often shows up late, and why getting evaluated quickly is the right decision both medically and practically.

Why the Sternum Gets Injured in Car Accidents

The sternum sits in the center of the chest, connecting the ribs through cartilage and protecting the heart, lungs, and major blood vessels behind it. Its central location and proximity to the vehicle's impact forces make it one of the more commonly injured structures in motor vehicle collisions. Three mechanisms are primarily responsible:

Seatbelt compression. A seatbelt works by rapidly tightening across the chest at impact to prevent ejection. The diagonal shoulder strap crosses directly over the sternum. In high-speed collisions or sudden hard stops, the compressive load can be significant enough to bruise the bone or cause a fracture — a pattern sometimes described as seatbelt syndrome. This is the most common cause of sternal injury in belted crash occupants.

Steering wheel and dashboard contact. When a driver's body moves forward at impact — particularly in severe crashes, in older vehicles, or when the belt stretches — the sternum can make direct contact with the steering wheel or dashboard. This blunt-force mechanism can cause more significant structural injury than belt loading alone.

Airbag deployment. Airbags deploy at extremely high speeds specifically to prevent contact with the vehicle's interior. However, the deployment force itself — particularly for shorter drivers seated close to the steering wheel — can cause direct impact to the sternum and surrounding chest wall.

These three mechanisms can occur independently or together in a single crash, which is why sternum injuries are common across a wide range of collision types, including low-speed rear-end impacts that most patients assume were not serious enough to cause structural injury.

Bruised Sternum vs. Fractured Sternum — The Difference Matters

Not all sternal injuries are equivalent. Understanding the distinction helps set expectations for recovery — and explains why imaging is not optional.

A bruised (contused) sternum involves damage to the soft tissue surrounding the bone and the outer layers of the bone itself, without a structural break. The bone remains intact. The area becomes tender, swollen, and often discolored. A bruised sternum typically heals in 2 to 4 weeks with appropriate rest and anti-inflammatory management. It is painful, but it is not structurally dangerous on its own.

A fractured (broken) sternum involves a crack or complete break through the bone. Sternal fractures are more common in car accidents than most patients expect — research indicates that motor vehicle collisions account for the majority of blunt chest trauma injuries in the United States. A sternal fracture:

Typically causes sharper, more intense pain than a bruise, especially with deep breathing, coughing, sneezing, or laughing
May produce a palpable sensation of cracking or movement over the sternum in more severe fractures
Requires X-ray or CT imaging for confirmation — it cannot be diagnosed by clinical examination alone
Takes 6 to 12 weeks to heal with appropriate management
Rarely, when the fracture is displaced or pressing on surrounding structures, may require further medical intervention

The critical point: pain intensity alone does not reliably distinguish a bruise from a fracture. Both are often very painful. Both can worsen significantly over the first 24 to 72 hours. Imaging is the only way to know what you are dealing with — and knowing changes the management plan.

Symptoms to Watch for After a Car Accident

The symptoms associated with sternal injury from a crash include:

Pain or tenderness directly over the center of the chest, typically worsened by pressing on the sternum
Pain that increases with deep breathing, coughing, sneezing, or laughing
Pain when lying in certain positions, particularly on your side or stomach
Swelling or visible bruising across the chest wall
Difficulty taking a full breath without triggering chest discomfort
A clicking, popping, or cracking sensation when moving the upper body in more severe injuries

Red-Flag Symptoms That Require Emergency Care

Some symptoms after a car accident go beyond what urgent care should manage. Go to the emergency room immediately or call 911 if you have:

Severe chest pain radiating to the arm, jaw, neck, or back
Shortness of breath that is worsening or prevents you from speaking in full sentences
Rapid or irregular heartbeat
Lightheadedness, dizziness, or feeling like you may pass out
Coughing up blood
Visible chest deformity
Signs of internal bleeding — sudden pallor, extreme weakness, or near-loss of consciousness

These symptoms can indicate a cardiac contusion, aortic injury, hemothorax, pneumothorax, or internal organ damage — all of which are life-threatening emergencies requiring immediate hospital-level care. If these are present, do not drive yourself. Call 911.

Why Your Sternum Pain May Not Have Started at the Scene

This is one of the most important things accident patients need to understand: the absence of immediate pain does not mean you were not injured.

At the moment of a crash, the body releases a significant surge of adrenaline (epinephrine) and cortisol as part of the acute stress response. These hormones narrow your focus, elevate alertness, and — critically — suppress pain signals. They function as a natural analgesic in the immediate post-impact period, which is why people involved in serious accidents can sometimes walk away from the scene feeling surprisingly okay, only to be unable to get out of bed the next morning.

Simultaneously, inflammation builds over the 24 to 72 hours following tissue trauma. As inflammatory mediators accumulate around the injury site, pain, stiffness, and tenderness increase. Many patients with sternal injuries first notice significant pain when they wake up the day after the crash, or when they try to take a deep breath and discover they cannot do so comfortably.

Delayed chest or sternum pain is not unusual — and it is not evidence that the injury is minor. It is a predictable physiological response to trauma. What it means practically is that patients who felt okay at the scene and are now experiencing chest discomfort 12, 24, or 48 hours later should still get evaluated.

Urgent Care vs. the Emergency Room: Making the Right Call

Not every post-crash chest injury requires an emergency room. Understanding when urgent care is appropriate — and when it is not — helps you get the right level of care efficiently.

Go to an emergency room immediately if you have:

Worsening shortness of breath or difficulty breathing
Chest pain radiating to the arm, neck, or jaw
Irregular or racing heartbeat
Lightheadedness or signs of shock
Any of the red-flag symptoms listed above

Urgent care is the appropriate setting if you have:

Chest or sternum tenderness without the red-flag symptoms above
Pain that developed hours or days after the crash
Pain with breathing, coughing, or movement
Swelling or bruising over the sternum or chest wall
Concern about whether imaging is needed

At Primary & Urgent Care, our Palm Beach County locations are equipped with digital X-ray, CT scanning, and diagnostic ultrasound — all available on a walk-in basis, same day, without appointment. That means the imaging you need to determine whether you have a bruise or a fracture is accessible today, without the ER wait time and associated cost.

How Sternum Injuries Are Evaluated and Treated

When you come in with chest or sternum pain following a car accident, the evaluation starts with a physical examination — assessing the location and character of the pain, whether it changes with breathing or movement, and reviewing exactly how the crash occurred and where the impact forces were directed.

Diagnostic imaging is ordered when a fracture is clinically possible:

Digital X-ray is typically the first study. It is fast, accessible, and identifies the majority of sternal fractures
CT scan provides more detailed imaging and is used when X-ray is inconclusive or when there is concern about surrounding structures — ribs, lungs, or thoracic spine
Ultrasound is particularly useful for evaluating rib cartilage and soft tissue structures adjacent to the sternum

Treatment is guided by findings:

For a bruised sternum: Rest, ice application (20 minutes several times daily for the first 48 hours), over-the-counter NSAIDs, and activity restriction — particularly avoiding lifting and overhead movement. Most patients see meaningful improvement within 2 to 4 weeks with consistent management.

For a sternal fracture: Similar conservative management with stricter activity restrictions. Deep breathing exercises remain important despite the discomfort, as shallow breathing over extended periods increases the risk of pulmonary complications. Pain management should be adequate enough to allow normal breathing. Most fractures heal in 6 to 12 weeks. Displaced fractures requiring further intervention are uncommon.

If follow-up is needed — whether for continued symptoms, referral to an orthopedic specialist, or additional imaging — we coordinate that from within the same visit.

Why Timing Matters Beyond Just Your Health

There are two reasons to get evaluated quickly after a car accident: a medical one and a practical one.

Medically, untreated chest injuries can develop complications that are harder to manage the longer they go unaddressed. Shallow breathing from pain avoidance can contribute to pulmonary complications. An unrecognized displaced fracture can shift. Inflammation that is not managed appropriately can extend recovery significantly.

Practically, Florida's Personal Injury Protection (PIP) insurance coverage requires that accident patients receive initial medical evaluation within 14 days of the crash to be eligible for benefits. A dated medical record documenting your injury, its mechanism, and the diagnostic findings is not just a clinical document — it is a foundational part of any insurance or legal process that follows.

Getting evaluated at a car accident injury clinic in Palm Beach County creates a clear, dated medical record that ties your sternum injury to the crash. For patients who go on to experience extended symptoms, require specialist care, or pursue a PIP or liability claim, that documentation is one of the most important things they will have.

Walk-in same-day evaluations are available at our Royal Palm Beach, Lake Worth, Palm Springs, and Lantana locations.