The clavicle is your collarbone, the long, slightly S-shaped bone that runs horizontally across the top of your chest on each side. It connects your shoulder to your trunk and is one of the most frequently broken bones in the body, accounting for 2.6 to 4% of all fractures in adults. You can feel it easily just below your neck, stretching from the base of your throat out to the tip of each shoulder.
Where the Clavicle Sits and What It Connects
The clavicle sits right at the front of your shoulder girdle, acting as a bridge between two other bones. On the inner end, it meets the breastbone (sternum) at a joint near the center of your chest. On the outer end, it meets a bony projection at the top of your shoulder blade. These two joints anchor the clavicle in place and give your shoulder its structural framework.
The bone itself has a gentle double curve. The inner half bows slightly forward, while the outer half curves back, giving it that distinctive S-shape. The inner two-thirds of the shaft is thicker and rounder, while the outer third flattens out. Several strong ligaments attach along the underside of the bone, connecting it to your shoulder blade and first rib to keep everything stable.
What the Clavicle Actually Does
The clavicle works like a strut or a brace, holding your shoulder out and away from your rib cage. Without it, your shoulder would collapse inward toward your chest. This spacing matters because it gives your arm the room it needs to move freely in all directions.
A cadaver study published in the Journal of Shoulder and Elbow Surgery demonstrated just how critical this role is. When researchers simulated a break in the clavicle, the shoulder blade shifted closer to the rib cage and lost significant range of motion. Specifically, the shoulder blade couldn’t rotate outward, tilt backward, or turn upward as well during arm movements. These changes were most dramatic when lifting the arm forward. In a living person, this kind of instability can make it harder to reach overhead and may lead to pinching of the soft tissues inside the shoulder joint.
Structures It Protects
The clavicle also serves as a shield. Running just behind and below it are major blood vessels and nerves that supply your entire arm. The subclavian artery and vein (the main blood supply heading to and from your arm) pass directly beneath the bone, along with the brachial plexus, a network of nerves that controls movement and sensation from your shoulder to your fingertips. The clavicle’s position over these structures provides a layer of bony protection that would otherwise leave them vulnerable to direct trauma.
How the Clavicle Develops
The clavicle holds a unique distinction: it is the first bone in the body to begin hardening during fetal development and one of the last to finish. While most of the bone solidifies early in life, the inner end doesn’t fully fuse until young adulthood. Studies using CT scans and skeletal collections consistently show that complete fusion at this inner growth plate typically happens between ages 20 and 25, though partial fusion can appear as early as 15 or 16.
This long fusion timeline is actually useful in forensic science. Because the stages of fusion at the inner end of the clavicle follow a predictable pattern, forensic investigators can estimate a person’s age from their clavicle with reasonable accuracy. By age 50, the inner end typically shows a fully fused, somewhat porous surface with blunted edges.
Why Clavicle Fractures Are So Common
The clavicle breaks more often than most bones for a simple reason: it’s exposed. Sitting just beneath the skin with no significant muscle padding, it absorbs direct hits from falls, contact sports, and car accidents. Its S-shape also creates a natural weak point near the middle of the bone, where the two curves meet and the cross-section is thinnest.
Data from the Swedish Fracture Register, covering over 2,400 fractures, confirms this pattern. About 69 to 82% of clavicle fractures happen in the middle third of the bone. Another 12 to 26% occur in the outer third, near the shoulder. Fractures of the inner third, near the breastbone, are rare, making up only 2 to 6% of cases. These fractures primarily affect young males, often from sports injuries or high-energy impacts.
What Recovery Looks Like
Most clavicle fractures heal without surgery. Treatment typically involves a sling to keep the arm still and pain management while the bone knits back together. The average healing time for a displaced midshaft fracture treated without surgery is about 9 weeks, with a range of 8 to 12 weeks.
Returning to normal life happens in stages. Most people can handle everyday activities like dressing, cooking, and light tasks around 6 weeks after the injury. Desk jobs and other sedentary work are usually manageable by about 7 weeks. Physically demanding jobs take longer, averaging around 10 weeks. Sports follow a similar timeline, with most athletes returning to activity between 9 and 11 weeks after the fracture.
Surgery becomes an option when the bone fragments are significantly displaced, when the fracture threatens the blood vessels or nerves underneath, or when the break occurs in the outer third near specific ligament attachments. But for the majority of clavicle fractures, time and a sling do the job.