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The Bone Heals on Its Own. It’s the Nail Bed Nobody Looks At.
A crushed fingertip usually heals in 3 to 4 weeks for the bone, with the tip protected in a small splint. If the nail is black and throbbing, get the blood drained in the first 48 hours. If the nail is split, torn, lifted or missing, get the nail bed checked the same day, cos it may need stitching. A new nail takes 4 to 6 months to grow out, and about a year to show its final shape.
Fingertip caught in a car door, hit with a hammer, crushed under something heavy. It’s throbbing, the nail is going black, and there might be a crack in the bone on the X-ray.
Here’s the counterintuitive part.
The fracture is usually the least important thing on that X-ray.
The fan-shaped tip of the fingertip bone is surrounded by tough tissue that splints it naturally, and these breaks reliably heal with nothing more than protection.
What decides whether your finger looks and works normally in a year is the nail bed underneath the nail, and whether anyone looked at it.
Miss a cut nail bed and you don’t find out for months. The new nail grows out ridged, split or lifting, by which point the simple repair is long gone. That’s a nail you look at every day, for good.
What is a tuft fracture?
The tuft is the fan-shaped end of the last bone in your finger, sitting right under the fingertip pad and the nail. Crush it and it usually cracks into a few pieces, held together by the pad on one side and the nail bed on the other.
That’s why the bone heals so reliably…and why the nail bed so often gets damaged in the same hit. They’re layers of the same sandwich.
How is a crushed fingertip assessed?
- An X-ray of that finger. Front and side views, to see the break, and whether it runs into the tip joint or across the base of the bone rather than through the fan-shaped end.
- The nail check. Is the nail intact and still tucked into its fold, or split, lifted or missing? This decides most of the treatment.
- The tip check. Can you straighten the tip joint on your own? If not, the tendon may have pulled off too.
- Circulation and feeling. Color, warmth, and sensation in the pad.
- The skin. Any wound over a broken tuft makes it an open fracture.
Should I drain the blood under my nail?
A dark red or black collection under the nail is a subungual hematoma: blood trapped between the nail and the bed, in a space that can’t expand.
That’s where the throbbing comes from, and it’s genuinely one of the more unpleasant kinds of pain in the hand.
Draining it takes literally just seconds.
A small hole is made through the nail, the blood escapes, and the relief is immediate. If your finger is throbbing under a black nail, this is worth going in for on day one rather than riding it out.
- Timing. It works best in the first 24 to 48 hours, while the blood is still liquid. After that it clots, and there’s less to gain.
- Size doesn’t decide it anymore. Older advice said a bruise covering more than half the nail meant pulling the nail off to check underneath. Current practice: if the nail and its edges are intact, drainage alone is usually enough, however big the bruise.
- No throbbing, no need. A small painless bruise under an intact nail can be left alone and will grow out.
(Please have someone do it properly rather than heating a paperclip at the kitchen table. Sterility matters here, particularly when there’s a fracture underneath, because that turns a closed break into an open one.)
Does a nail bed injury need stitches?
Not how much blood is under the nail. Whether the nail itself is still intact and properly seated. That’s the question that actually matters.
- Nail plate intact, edges still tucked under the skin folds: the nail bed underneath is probably fine. Drain the blood, protect the finger, leave the nail alone.
- Nail split, torn, partly lifted out from its fold, or missing: the nail bed under it has very likely been cut, and it should be looked at and repaired.
Repairing it means lifting the nail, stitching the nail bed back together with fine sutures, and replacing the nail or a substitute to hold the fold open while it heals.
A nail bed that heals with a ridge of scar in it grows a ridged, split or lifting nail from then on. Permanently.
That’s the whole argument for taking a squashed fingertip to someone on the day rather than waiting to see how it settles. The bone will be fine either way.
The nail is a one-shot repair.
Crushed fingertip healing time, step by step
- Day one: a throbbing black nail gets drained. A split, torn or lifted nail gets the nail bed checked and, if it’s cut, repaired.
- If the bone is broken under a torn nail, that’s an open fracture, and antibiotics are often given.
- Weeks 1 to 4: a small splint over the tip protects the bone and the repair. Dressings kept clean and dry. See fingertip protector splints.
- Weeks 2 to 3: stitches dissolve or come out. Whatever was placed under the nail fold stays until your clinic says otherwise.
- From week 3 or 4: splint off for most people, desensitization and normal use. The guarding stops here. Longer protection if the break runs across the base of the bone.
- Months 4 to 6: a new nail grows out to the tip.
- Around 1 year: the final look of the nail, and usually the end of the cold sensitivity.
The X-ray can keep showing a line through the tuft for months after the finger feels fine. Common, and usually not a problem if the tip isn’t painful to press.
Will a damaged nail bed grow back?
Usually, yes. It depends on WHICH part got damaged.
- The nail grows from its root, the part hidden under the skin fold above the nail. If the root survives, a nail grows back.
- The nail bed underneath decides the SHAPE of that new nail. A bed that healed flat grows a flat nail. A bed that healed with a scar ridge grows a ridged, split or lifting nail.
- If the root itself was badly crushed or lost, parts of the nail may never come back, or it may grow back permanently deformed.
- Repair in the first days gives the bed its best chance of healing flat. Weeks later, a deformed nail can sometimes be improved surgically, but it’s a harder job with less certain results.
The nail bed runs on a short window. OPEN in the first few days, when a cut bed can be stitched flat. CLOSING over the next week or two, as it heals in whatever shape it’s lying in. SHUT once the new nail grows out wrong.
Which is why “just a black nail” deserves a proper look on day one, not month four, when the new nail grows out wrong and the window for a simple repair has already shut.
What will the new nail look like?
Expectations, so nothing surprises you:
- The old nail often lifts off. A badly bruised nail usually comes away over several weeks. That’s normal and not a complication.
- Growth is slow. Fingernails grow at roughly 3mm a month, so a completely new nail takes around 4 to 6 months to reach the end of the finger.
- It looks strange for a while. Thickened, ridged, or slightly discolored. Judge the final result at about a year, not at three months.
- The fold has to stay open. That’s why something gets placed back under it after a repair, and why you shouldn’t pull it out early.
For what specific ridges, lines and color changes mean, see nail changes after a hand injury.
Nail lifted or detached after an injury: what to do
- Don’t rip it off. A loose nail still acts as a natural dressing over the bed underneath.
- Trim the loose edge if it’s catching on things, and keep it covered with a light dressing.
- If the bed underneath is exposed, raw or bleeding, or the nail came off in the injury itself, get it seen. That’s a nail bed injury until proven otherwise.
- If it’s lifting slowly weeks after a bruise, with the bed underneath already dry and healed, that’s usually just the old nail making way for the new one.
Why is my fingertip still sensitive or numb?
The part nobody warns you about: the fingertip unfortunately stays sensitive.
There’s more nerve ending per square centimeter in that pad than almost anywhere on your body, so after a crush injury it can be painfully oversensitive, oddly numb in patches, or both, for months.
Cold intolerance is common and can last a year or more!
This responds well to desensitization and to using the finger deliberately rather than guarding it. Protecting a sensitive fingertip keeps it sensitive, which is the opposite of what instinct says. (The finger that hides in a fist for six weeks is the one still yelping at a keyboard in month four.)
Exercises after a crushed fingertip
Start these once the splint comes off and the skin is closed, usually around week 3 or 4. Your clinic may adjust.
- Texture ladder. Rub the pad over a texture for 2 to 3 minutes, 3 to 4 times a day. Start soft (cotton wool, silk), move to a towel, then a bowl of dry rice, then lentils or beans. Move up a level when the current one feels odd rather than painful.
- Tapping and pressing. Tap the pad gently on a tabletop for 1 to 2 minutes, then press and hold on the table for 10 seconds, 5 times. Build the pressure over days.
- Tip bends. Hold the middle segment of the finger still and bend only the tip joint. Hold 3 seconds, 10 reps, 4 to 5 times a day. The tip joint stiffens quickly after a few weeks in a splint.
- Use it on purpose. Typing, buttons, coins, picking up small things. The pad has to go back to work to stop complaining.
If the whole finger or hand is still puffy, swelling control comes first. See crush injury swelling and recovery.
When can I go back to work, drive and play sport?
- Desk work: usually within 1 to 3 days, tip protected, typing with the other fingers at first.
- Driving: once you can grip the wheel firmly without the tip stopping you. Usually within the first week or so.
- Light manual work: often 1 to 2 weeks with a fingertip protector on.
- Heavy gripping, tools, anything that knocks the tip: around 4 to 6 weeks. See returning to work after a hand injury.
- Ball sports, climbing, martial arts: around 4 to 6 weeks with the tip protected, once the nail bed has healed and the skin is closed.
If it’s a child’s finger, the rules are a bit different, and the nail bed matters even more. See a child’s finger crushed in a door.
Get it checked today if
- The fingertip stays white, blue or cold. Go to the ER now.
- Tissue is actually missing from the end of the finger, rather than crushed. That’s a fingertip injury or amputation.
- The nail is split, torn, lifted out of its fold or missing, or there’s bone showing.
- The nail is black and throbbing and hasn’t been drained, especially in the first 48 hours.
- The tip won’t straighten on its own afterwards. Check for mallet finger, because the tendon can be pulled off in the same accident.
- Increasing redness, throbbing that worsens after day two, pus or discharge. An open tuft fracture is a real infection risk. See finger infections.
Get it checked if
- The tip is still too sensitive to use after 6 weeks of desensitization.
- The tip joint is stiff after the splint comes off and isn’t loosening.
- The new nail is growing out ridged, split or lifting.
- The tip is still painful to press at 3 months.
The fracture will heal. The nail is the part with a deadline.
Written by Nigel Chua, hand occupational therapist in practice since 2005. Thousands of hands, wrists and elbows assessed and treated. My credentials are here. This article explains; it doesn’t examine. A crushed fingertip with a disrupted nail should be seen the same day.
Every article on this site is written using the Closing Window Method: name the window your condition runs on, find where you are in it, and act while it’s still open.