The Half Moon Nail

aka Bone and Joint Bamboozler 006

40 year old male attends with acutely painful toe following a weekend DIY incident.

[Sledgehammer 1 – Man 0]

What is the diagnosis?

Bamboozler Answer

Subungual Haematoma

  • Subungual haematomas occur when there is bleeding beneath the nail. Generally caused traumatically by getting it caught between to hard surfaces.
  • The haematoma becomes trapped between the rigid structures of the nail above and the distal phalanx below.
  • The space occupying mass causes intense pain secondary to increased pressure against the very sensitive nail bed and matrix.

How would you assess this injury?

Bamboozler Answer

Examination should include:

  • Testing extensor and flexor tendons
  • Testing circulation by capillary refill
  • Checking the sensitivity to the area


  • X-rays are generally indicated to rule out crush injury or fracture to the distal phalanx
  • Document the percentage of nail bed covered by the haematoma, surrounding damage to tissues, nail-bed, and nail margins.

What are the potential complications?

Bamboozler Answer
  • Fracture to the distal phalanx
  • Crush injury
  • Nail bed injury
  • Performing trephination on subungual ecchymosis.

If no history of trauma or story doesn’t fit with subungual haematoma consider melanoma, Kaposi’s sarcoma, and other tumors.

What are the treatment options?

Bamboozler Answer

Wait and See:

Patients who are not experiencing significant pain at rest, should not have trephination performed, and can be treated with simple analgesia, rest, ice, and a protective splint.


Trephination gives good cosmetic and functional result in both adults and children as long as no other fingertip injury is present.

Trephination makes a closed wound open, and introduces the risk of bacteria entering causing infection, once procedure completed and haematoma evacuated no need to further soak digit, and a protective dressing should be applied for 7-10 to prevent infection.

LITFL: Subungual haematoma trephination. Procedure


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