5 Things You Need to Know About Boxer's Fractures
Boxer's fractures are common
Along with finger (phalanx) fractures and scaphoid fractures, boxer's (fifth metacarpal) fractures are the most common hand fractures. This is the bone leading up to the pinkie finger. The other metacarpals are more cushioned by the muscles and soft tissues of the palm. The fifth metacarpal doesn't have as much meat to protect it, and it's usually the first bone to strike something.
I have never seen a wall lose
Most boxer's fractures are caused by a closed fist striking something, often in anger. While this object can be another person (hence the name), I've found that most boxer's fractures happen when a person hits an immovable object. This can be a brick wall, door, pole, table, car or even the ground. Any way you want to put it, I've never seen these things lose. Next time you're angry and want to hit something, think about it. Maybe find a nice soft pillow or beanbag instead.
Most fractures go into flexion
Because the fist is closed and the metacarpal head strikes the object first, the bone is usually bent down toward the palm (flexion). This causes pain and swelling at the fracture site. You will likely be unable to move the pinkie finger.
Luckily, most of these will heal without surgery
The fifth metacarpal can tolerate quite a bit of angulation. This is because the carpometacarpal (CMC) joint has a large range of motion. Hold your hand up in front of you with the fingers pointed straight up. Turn your hand sideways so that all the fingers overlap. Use your other hand to grab the fifth metacarpal, just below the knuckle. Move it back and forth, toward and away from the palm. See how much motion there is at the CMC joint? If you repeat this for the second metacarpal to your index finger, you will see that there is not much motion there. Because of the wide range of motion at the fifth CMC joint, you can tolerate quite a bit of angulation of the fifth metacarpal and still have a very high functional level.
What this means for you
In the end, most of these will heal in a cast, unless the doctor feels that you would be better served with surgery. You will notice that the fifth knuckle looks like it has moved closer to the wrist. What has really happened is that the real knuckle (metacarpal head) has been depressed by the injury. This means that it has gotten pushed down toward the palm and is not as prominent. The new "knuckle" is actually the point of the fracture which heals with a bunch of new bone, forming a bump on the back of your hand.
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