A 35-year-old woman with long-standing oral and nail lichen planus develops a split extending from the proximal nail fold into the nail plate, dividing it into two halves. The structure responsible for this deformity is scarring between the:
- A Proximal nail fold and the germinal matrix ✓
- B Lateral nail fold and nail bed
- C Hyponychium and distal nail bed
- D Eponychium and lunula
Correct answer: A. Proximal nail fold and the germinal matrix
Explanation
Dorsal pterygium is a wedge-shaped scar uniting the proximal nail fold to the germinal matrix, splitting the growing plate into two strips. It signals focal destruction of the matrix and is seen in lichen planus, graft versus host disease and after trauma. Involvement of the matrix explains why the defect is permanent unless the scar is surgically released. Hyponychial changes cause distal onycholysis, not a proximal split.
Reference: Fitzpatrick's Dermatology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.