MNT Nail Anatomy and Pathology 1 — Questions and Answers
Question 1: What is the name of the crescent-shaped white area at the base of the nail plate?
- Hyponychium
- Lunula (Correct answer)
- Eponychium
- Nail matrix
Correct answer: Lunula
The lunula is the visible portion of the nail matrix that appears as a white crescent at the proximal nail plate base.
Question 2: Which structure produces the nail plate?
- Nail bed
- Nail matrix (Correct answer)
- Hyponychium
- Lateral nail fold
Correct answer: Nail matrix
The nail matrix contains the germinal cells responsible for nail plate production; damage to the matrix can result in permanent nail deformity.
Question 3: Onychogryphosis is characterized by:
- Nail pitting and oil-drop discoloration
- Extreme nail thickening and curved, claw-like deformity (Correct answer)
- Horizontal ridging of the nail plate
- Separation of the nail from the nail bed
Correct answer: Extreme nail thickening and curved, claw-like deformity
Onychogryphosis (ram's horn nail) involves marked thickening and distorted curvature of the nail plate, typically affecting the great toenail in elderly patients.
Question 4: Beau's lines are best described as:
- Longitudinal melanonychia
- Transverse grooves across the nail plate indicating a prior systemic illness or trauma (Correct answer)
- White spots from minor trauma to the nail matrix
- Subungual hemorrhage streaks
Correct answer: Transverse grooves across the nail plate indicating a prior systemic illness or trauma
Beau's lines are transverse depressions caused by temporary arrest of nail matrix cell division during systemic illness, malnutrition, or major stress.
Question 5: The hyponychium is located:
- Proximal to the nail matrix
- At the distal end where the nail plate separates from the nail bed (Correct answer)
- Along the lateral nail folds
- Beneath the lunula
Correct answer: At the distal end where the nail plate separates from the nail bed
The hyponychium is the epithelial seal at the distal free edge of the nail, forming a barrier against pathogen entry between the nail plate and nail bed.
Question 6: Koilonychia refers to nails that are:
- Thickened and yellow
- Spoon-shaped with raised edges (concave), associated with iron deficiency anemia (Correct answer)
- Pitted and crumbled
- Separated from the nail bed
Correct answer: Spoon-shaped with raised edges (concave), associated with iron deficiency anemia
Koilonychia presents as spoon-shaped (concave) nails, classically associated with iron deficiency anemia and hemochromatosis.
MNT Nail Anatomy and Pathology 1
What is the name of the crescent-shaped white area at the base of the nail plate?