A “half-broken” nail, which describes a crack or fracture in the visible nail plate, cannot fuse itself back together. The nail plate is made of translucent keratin protein, composed of dead, compacted cells that protect the underlying tissue. Because the nail plate is non-living, it lacks the biological mechanisms—like cell division and blood flow—required for true healing or repair. The only way to resolve a crack or break is through the continuous, forward growth of a new, healthy nail from the root.
Understanding Nail Growth and Replacement
The process of forming a new nail originates in the nail matrix, located at the base of the nail plate beneath the skin fold. This tissue generates new cells that harden through keratinization, eventually becoming the rigid nail plate. As the matrix continuously produces new cells, it pushes the older, damaged nail plate forward over the nail bed.
This constant forward movement is the mechanism by which any damage is eventually replaced by healthy nail tissue. The speed of this replacement varies significantly, but a full fingernail replacement takes approximately six months. Fingernails grow at an average rate of about 3.47 millimeters per month.
Toenails grow at a much slower pace, as they are subjected to less friction and have less blood circulation than fingers. Their average growth rate is about 1.62 millimeters per month, meaning a full toenail replacement can take up to 18 months. The time it takes for the broken section to grow past the fingertip depends on the crack’s location and the individual’s growth speed.
Immediate Care for a Cracked or Partially Broken Nail
While the nail cannot heal itself, immediate care is necessary to prevent the crack from snagging, tearing further, or injuring the sensitive nail bed beneath. The first step involves gently filing or trimming any sharp or jagged edges to prevent the break from extending deeper. If the break is minor, smoothing the edges can manage the injury until the nail grows out.
Temporary Stabilization
For a crack that extends across the nail but does not involve the skin, temporary stabilization protects the underlying tissue. This involves using a small piece of material, such as a section cut from a tea bag or silk wrap, as a stabilizing patch. Apply the patch directly over the crack using a thin layer of nail glue or a strong base coat polish.
Once the adhesive has dried, gently buff the surface smooth to create a natural finish and prevent the patch from catching. This temporary repair stabilizes the damaged section until the crack has grown far enough to be safely trimmed away. Keeping the area clean and dry is important to avoid external contamination.
Recognizing Serious Damage and Infection
A simple nail crack becomes a more serious medical concern when the damage extends to the living tissue of the nail bed or the matrix. Severe trauma, such as a crush injury, may cause significant bleeding under the nail, known as a subungual hematoma, which presents as black or purple discoloration. Professional medical attention is advised if blood covers more than half of the nail, if there is severe throbbing pain, or if you cannot bend your finger or toe.
Any break that exposes the nail bed creates an entry point for bacteria and fungi, increasing the risk of infection. Signs of a developing infection include increasing redness, tenderness, and swelling of the skin around the nail, known as the nail fold. The presence of pus or discharge, warmth in the area, or persistent, worsening pain indicates the injury requires evaluation by a healthcare professional.