Last Updated on February 6, 2025
Nail bed injuries is a type of fingertip injury that involves the bed of the fingernail. which consists of the nail matrix. Nail bed injuries may affect the sterile matrix and germinal matrix.
In general, germinal matrix injuries are more serious. An injury in this region has a higher likelihood of permanently affecting nail growth.
The nail is an integral component of the digital tip. It is a unique hardened structure formed by keratinized squamous cells. Nail functions to protect the fingertip and provides a counterforce to tactile sensation and aids in the grip formed by fingertips [ as in pinching].
It is also involved in temperature control [thermoregulation] which is regulated by glomus bodies in the nail bed and matrix.
Nail bed injuries are a type of fingertip injury and occur as the result of direct trauma to the fingertip. There is 3:1 male-to-female predominance
Parts of The Nail

Nail Plate
The nail plate is also called corpus unguis. It is the hard visible part of the nail. The nail plate is composed of hard, keratinized, squamous cells that are loosely adherent to the germinal matrix but strongly attached to the sterile matrix.
Matrix
Matrix is the tissue that a nail [nail plate] protects. It lies beneath the nail and contains nerves, lymph, and blood vessels. The matrix is responsible for producing cells that become the nail plate. It has two parts sterile and germinal.
The sterile matrix is distal to the lunula and adheres to the nail. The germinal matrix is proximal to the sterile matrix and the insertion of the extensor tendon is approximately 1.2 -1.4 mm proximal to the germinal matrix
Lunula
The lunula is the white area at the base of a fingernail. Lunula means little moon. The lunula represents the distal extent of the germinal matrix.
It is located at the proximal end of the nail and lies under the nail.
It is white only when seen through the nail. The lunula damage to lunula will cause permanent deformation of the nail.
Hyponychium, Eponychium and Paronychium
The hyponychium is the epithelium located beneath the nail plate at the junction between the free edge of the nail and the skin of the fingertip.
The eponychium is the small band of epithelium that extends from the posterior nail wall onto the base of the nail.
Paronychium is the lateral nail folds on either side of the nail plate.
Blood Supply
Terminal branches of the radial and ulnar proper palmar (volar) digital arteries supply the nail. Nail growth is separated from the germinal matrix, sterile matrix, and dorsal roof of the nail fold. Nail growth is estimated at 3-4 mm per month.
Cause of Nail Bed Injuries
Any crushing or direct force can cause nail bed injury. The mechanism of injury may include
- Fingertip getting crushed between two objects
- Finger caught in a closing door
- Saw injury
- Direct blow with a hammer or another heavy object
- Avulsion/Amputation by chopping machine
Depending on the severity of the injury associated bony, tendon, or joint injuries may be present.
Types of Nail Bed Injuries
Nail bed injuries can be
- Subungual hematoma: A hematoma below the nail creating a separation between nail and the matrix.
- Nail bed laceration: This occurs when a nail bed gets injured by a sharp cut
- Nail bed avulsion: Often caused by fingertip being squeezed by the door or direct injury by force
Clinical Presentation of Nail Bed Injuries
The patient with injury would present with pain, swelling, and inability to use the digit. There could be a variable amount of external bleeding depending on the severity of the external wound.
The finger should be examined in detail to assess the injury and its severity. A closed injury with visible hematoma/discoloration of the nail should raise the concern of subungual hematoma. In lacerations and avulsions, nail integrity should be assessed.
Imaging
AP, lateral, and oblique of the finger should be done to ascertain or rule out a fracture of the distal phalanx of the involved digit.
Treatment of Nail Bed Injuries
Treatment of nail bed injuries depends on the type and severity of the injury.
Subungual Hematoma
This is caused by crushing injury mostly and results in bleeding under the nail. Mionrhematomas can be managed conservatively with warm compresses, painkillers etc.
Very painful hematomas would require drainage by making a hole in the nail [trephination] using a cautery needle. If the nail involvement is more than half of the area, nail bed repair is indicated as below.
Nail Bed lacerations
These nail bed injuries are seen in the present either
- A subungual hematoma greater than 50% of the nail surface area
- nail lacerations reaching the matrix
- Nail bed repair is done by removing the nail and inspecting the matrix for laceration. Using fine absorbable sutures [6-0] the repair of the matrix is done. The nail is placed back and sutured to the eponychial fold and reinforced by paronychial-nail sutures as well.
- The usual wound precautions like antibiotics and tetanus prophylaxis are done.
Avulsion Injuries
The high-energy nail bed injuries can cause the avulsion of nails and a portion of the underlying nail bed. It is often associated with other injuries including distal phalanx fracture. The treatment is nail removal and repair of the nail bed. A splint or K-wire fixation may be required for distal phalanx fracture. Nail bed avulsions account for approximately 15% of all traumatic injuries to the nail. For treatment, the avulsed nail bed is sutured in an anatomic position. If the avulsed nail cannot be sutured back, a split-thickness nail matrix graft can be used.
After repair, the nail is replaced as it serves as a template for the newly growing nail and provides a biological dressing.
The finger is protected and motion is restricted for 7-10 days.
Complications of Nail Bed Injuries
Nail bed injuries can lead to a number of nail abnormalities. Commonly encountered nail deformities are nonadherence, split nails, linear ridging, crooked nails, and hooked nails.
Nonadherence
Nonadherence occurs when the nail does not adhere to the abnormal scar that has formed within the injured nail bed. It is the most common nail deformity after nail bed injuries. It could be distal nonadherence or proximal one.
Distal nonadherence can cause a problem of dirt being lodged underneath the nail. Proximal nonadherence can cause instability of the nail.
Treatment is by scar excision and primary repair. Split-thickness nail grafting may be done where required.
Split Nail
Split nails occur because of a longitudinal scar in the germinal or sterile matrix. The nail, therefore, grows on either side of the scar in the germinal matrix.
Treatment is done by scar excision and replacement with a split-thickness matrix graft.
A split nail due to an abnormality in the germinal matrix requires a germinal matrix graft from another finger or toe.
Linear Ridging
Linear ridging is often secondary to a bony protuberance beneath the nail bed.
Incising the nail bed over the involved area, removal of protruding bone, and reapproximation of the nailbed is the treatment performed.
Lateral Deviation
Full-thickness avulsion of the lateral aspect of the nail bed causes the deviation of the nail. Elevation of the entire nail bed and placing it in a straight position is the recommended treatment.
Hooked Nail
A hooked nail involves volar displacement of the distal aspect of the nail. It can occur following a malunited fracture or a deficiency of skin of the digital pulp.
It is treated by freeing the tethered pulp and nail bed, splinting the freed nail bed, and reconstructing the soft-tissue defect of the pulp.
Total Nail Loss
Total nail loss can be treated by split-thickness skin grafting, nail prosthesis, or total nail reconstruction.
References
- George A, Alexander R, Manju C. Management of Nail Bed Injuries Associated with Fingertip Injuries. Indian J Orthop. 2017 Nov-Dec;51(6):709-713. doi: 10.4103/ortho.IJOrtho_231_16. [Link]
- Tos P, Titolo P, Chirila NL, Catalano F, Artiaco S. Surgical treatment of acute fingernail injuries. J Orthop Traumatol. 2012 Jun;13(2):57-62. doi: 10.1007/s10195-011-0161-z. Epub 2011 Oct 8.
- Pingel C, McDowell C. Subungual Hematoma Drainage. 2023 Jul 25. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan–. [Link]