Hairline fractures, so named because they look like a piece of hair on x-ray, can affect any of the wrist bones. They are small cracks in the bone that do not cause the bone pieces to separate. Hairline fractures in the wrist are usually due to a specific injury, such as when people reach forward with their hand to catch themselves during a fall, causing the weight of their body to be transmitted to the wrist. A direct hit to the wrist, as may occur during sports activities or car accidents, may also cause a hairline wrist fracture. Symptoms range from pain and tenderness to bruising, swelling and reduced movement.
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Pain and Tenderness
Pain is a common symptom of hairline wrist fractures. When the fracture is caused by a specific injury, the pain occurs immediately. It is generally sharp at first, but may then improve to become a less severe, duller pain. The pain worsens when moving the wrist, such as when lifting objects. Tenderness -- the sensation of pain when an area is touched -- also occurs with these fractures. With small hairline fractures, pain may be minimal but tenderness will be significant.
Bruising and Swelling
Bruising often occurs with hairline wrist fractures as blood vessels in the bone or surrounding tissues are damaged, leaking blood into the area. The bruise is typically black or blue when it first appears. Over the next few days, the color will change and the bruise may spread to cover a larger area. With time, the body will eventually reabsorb the blood and the bruise will shrink, then disappear.
Hairline wrist fractures often produce swelling as well. A certain amount of swelling occurs with any large bruise. Swelling is also caused by inflammation in the area due to the injured bone and surrounding tissues. This causes fluid to build up around the injury site. Swelling begins soon after the fracture and generally worsens over the next several hours.
Pain, bruising and swelling with hairline wrist fractures can prevent the wrist from moving as well as normally. But because the pieces of bone remain in place with a hairline fracture, it is still possible to move the wrist to some extent. This is one way that hairline fractures are different from many major breaks, which prohibit all movement. Although the wrist can move, eliminating movement with a splint or cast will help reduce pain and promote healing.
Seeking Medical Attention
If you have symptoms of a hairline wrist fracture, see your doctor to determine whether your bone is actually broken. An x-ray is needed to properly diagnose a fracture. However, because hairline fractures are so small, they are sometimes not seen on an initial x-ray, so the x-ray may need to be repeated at a later time. Scaphoid fractures, a common type of wrist fracture occurring on the thumb side of the wrist, are often not clearly visible on the first x-ray.
Reviewed by: Mary D. Daley, M.D.