What Causes a Broken Collarbone?

Most clavicle fractures are the result of trauma or a direct impact. The force required to break this bone can come from several different scenarios, but it almost always involves a sudden, forceful event.

Direct Blows to the Shoulder:

The most frequent cause is a direct blow to the side of your shoulder. This can happen in various ways:

• Falls: A hard fall directly onto the point of your shoulder is a classic cause. This could be a slip on ice, a fall from a bicycle, or tumbling during a sports activity.
• Contact Sports: Athletes involved in contact sports like football, hockey, rugby, or wrestling are at a higher risk. A forceful tackle or check that impacts the shoulder can easily fracture the clavicle.
• Accidents: Motor vehicle accidents, whether in a car, on a motorcycle, or a bicycle, often involve significant impact forces that can lead to a broken collarbone.

Falls onto an Outstretched Arm:

Sometimes, the force that breaks the collarbone doesn't even hit the shoulder directly. If you fall and instinctively put your arm out to catch yourself, the impact travels up the arm. This concentrated force can be strong enough to break the clavicle when it reaches the shoulder area. This is a very common mechanism of injury for people of all ages.

Age-Related Factors:

While trauma is the primary cause, age can play a role in how easily the bone breaks. In younger, active individuals, a clavicle fracture typically requires a significant amount of force, such as a high-impact sports injury. In older adults, however, the bones may be weaker due to conditions like osteoporosis. For an older person, a much less severe fall—one that might only cause a bruise in a younger person—can be enough to fracture the collarbone.

The clavicle is not equally strong along its entire length. The middle portion of the bone, known as the mid-shaft, is the thinnest and least supported part. As a result, it is the most vulnerable area and the site of the vast majority of clavicle fractures—around 70-80% of them, in fact. Fractures can also occur closer to the shoulder end (distal) or closer to the breastbone end (medial), but these are much less common.

The break itself can range in severity. It might be a simple, non-displaced crack where the bone remains perfectly aligned. In other cases, it can be a complete break where the bone separates into two or more pieces. If these pieces move out of their normal position, it is called a displaced fracture. In a severely displaced fracture, the bone fragments might overlap or angle sharply, creating a noticeable bulge under the skin.

Recognizing the Symptoms of a Broken Collarbone

A broken collarbone is almost always immediately obvious due to the pain and other distinct symptoms it causes. If you have fractured your clavicle, you will likely experience some or all of the following signs:

• Intense Shoulder Pain and Inability to Lift Your Arm: This is the most prominent symptom. The pain is usually sharp, located directly over the collarbone, and worsens with any attempt to move the arm or shoulder. Lifting your arm may feel impossible due to the pain and the mechanical instability of the broken bone.
• A Sagging or Drooping Shoulder: The clavicle acts as a strut that holds the shoulder up and away from the body. When it breaks, this support is lost, and the shoulder on the injured side may appear to slouch downward and forward compared to the uninjured side.
• Visible Deformity or Bump: In many cases, a noticeable bump or deformity will appear over the fracture site. This is caused by swelling and, in displaced fractures, by the end of the broken bone pushing up against the skin. The area can look swollen and out of alignment.
• Grinding or Crackling Sensation (Crepitus): When you try to move your shoulder or arm, you might feel or even hear a grinding or crunching sensation. This is called crepitus, and it is caused by the broken ends of the bone rubbing against each other.
• Bruising, Swelling, and Tenderness: The area over the collarbone will become swollen, tender to the touch, and will typically develop significant bruising within a few hours or days. The skin over the break can be very sensitive.
• Numbness or Tingling (Rare): In rare instances, a sharp fragment of the broken clavicle can press on or injure the nerves and blood vessels that run nearby, on their way to the arm. This could cause symptoms like numbness, tingling, coolness, or a pale color in your arm or hand. These are urgent warning signs that require immediate medical attention.

Another rare but serious sign is "tenting" of the skin, where a sharp piece of bone pushes so hard against the skin from underneath that it creates a tent-like peak. If the bone actually breaks through the skin, it is called an open fracture and is considered a medical emergency.

If you experience these symptoms after an injury, it is important to seek a medical evaluation. Most people instinctively protect the injured arm by holding it close to their body, often supporting the elbow with their other hand to relieve pressure on the shoulder.

How is a Broken Collarbone Diagnosed?

Diagnosing a clavicle fracture is usually a straightforward process for a healthcare provider. The evaluation typically involves a physical examination followed by imaging.

Physical Examination:

A doctor can often suspect a broken collarbone just by looking at the shoulder and listening to your description of the injury. They will look for the classic signs like swelling, deformity, and a drooping shoulder. They will gently feel along your collarbone to pinpoint the area of tenderness and assess the position of the bone fragments. During the exam, the provider will also check for any complications. This includes:

• Checking the skin over the fracture to ensure it is not broken or "tented."
• Assessing the nerve function in your arm and hand by checking sensation and your ability to move your fingers and wrist.
• Checking the blood flow to your arm by feeling for a pulse at your wrist and observing the color and temperature of your hand.

Imaging:

To confirm the diagnosis and get a clear picture of the break, an X-ray is necessary. X-rays will show the exact location of the fracture, whether it is in the middle of the bone or near one of the ends. More importantly, the X-ray reveals the fracture pattern—is it a simple crack or broken into multiple pieces?—and the degree of displacement. The doctor needs to see how far the bone fragments have shifted from their normal alignment. Often, the X-ray will include the entire shoulder girdle to make sure no other bones, like the scapula or humerus, were injured at the same time.

In more complex cases, such as when the fracture extends into a nearby joint or is broken into many small pieces (a comminuted fracture), a CT (Computed Tomography) scan may be ordered. A CT scan provides a much more detailed, three-dimensional view of the bone, which can be crucial for understanding the injury and planning the best course of action.

The General Healing Process for a Clavicle Fracture

While specific treatment plans are determined by a medical professional, the general approach for most clavicle fractures focuses on allowing the bone to heal naturally. The human body has a remarkable ability to mend broken bones, and the collarbone is no exception.

Most broken collarbones, especially those in the middle of the bone that are not severely displaced, can heal well without surgery. The standard approach is immobilization. Your arm will be placed in a sling or a special figure-of-eight brace. The purpose of the sling is to support the weight of your arm, which takes the pressure off the broken clavicle and keeps the shoulder from moving too much. This allows the bone ends to remain relatively still so the healing process can begin.

You will typically wear the sling for several weeks. During the first few days, pain management is important. This may involve pain medication and applying ice packs to the area to help reduce swelling and discomfort.

Even while the shoulder is immobilized, your doctor will likely encourage you to do gentle motion exercises for your elbow, wrist, and fingers to prevent them from becoming stiff. As the bone starts to heal and the pain subsides, you will be guided to begin gentle range-of-motion exercises for the shoulder itself. This is a critical step to prevent long-term stiffness.

A broken collarbone in an adult usually takes about 6 to 8 weeks to knit together. Healing time can vary based on your age, overall health, and the severity of the fracture. Follow-up X-rays will be taken periodically to monitor how the bone is healing. These images will show the formation of a "callus," which is new bone that bridges the gap between the broken fragments.

Once there is enough evidence of healing, you will gradually be weaned off the sling and begin a more active rehabilitation program. This often involves physical therapy to restore your shoulder's flexibility, range of motion, and strength. Regaining full function can take several months, but consistent effort with therapy exercises leads to the best outcomes.

In cases where the bone fragments are significantly out of place (severely displaced), have pushed through the skin (open fracture), or if the bone is shortened due to overlapping fragments, surgery may be considered to realign the pieces and hold them together with plates and screws. However, the decision to proceed with surgery is complex and depends on many factors.

Outlook and Potential Complications

The outlook for a broken collarbone is generally very good. The vast majority of people who experience this injury heal well and are able to return to all their normal activities without long-term problems.

It is normal for a hard lump to form at the fracture site as the bone heals. This bony callus is a natural part of the healing process. While it might be quite prominent at first, this lump typically remodels and becomes smaller over many months to a year. In some cases, a slight, permanent bump may remain, but this is usually just a cosmetic issue and does not cause pain or affect function.

While complications are not common, they can occur.

• Delayed Healing or Nonunion: Sometimes, a bone can heal very slowly or fail to heal completely. This is called a nonunion. The risk is higher in severely displaced fractures, in smokers, or in individuals with certain health conditions. A nonunion may result in ongoing pain and poor shoulder function and might require further intervention.
• Malunion: This occurs when the bone heals in an incorrect position. For example, if the broken ends heal with significant overlap, the clavicle may end up shorter than it was before the injury. While minor shortening rarely causes issues, a significant malunion could potentially affect shoulder mechanics and strength.
• Nerve or Blood Vessel Injury: As mentioned, this is a rare but serious complication. The close proximity of the clavicle to the bundle of nerves and blood vessels supplying the arm means a sharp bone fragment could cause damage. Any new or persistent numbness, weakness, or circulation problems in the arm should be reported to your doctor immediately.
• Post-Traumatic Arthritis: If the fracture occurs at either end of the clavicle and damages the joint surface (either the AC joint at the shoulder or the SC joint at the chest), there is a risk of developing arthritis in that joint years down the road.

Overall, with proper medical care and dedicated rehabilitation, you can expect to make a full recovery from a broken collarbone. Patience is key, as it takes time for the bone to solidify and for your muscles to regain their strength and coordination.