To these we refer:
1. Clinical form (distal/lateral, proximal or superficial)
2. Depth of nail involvement
3. Thickness of subungual hyperkeratosis.

What we do not consider as key factors are: number of the nails affected -- the key is not this but the most affected and slow-growing nail; lateral involvement -- the key is only the proximity of a lesion to matrix area (longitude) irrelative to latitude; severity of onycholysis -- it is absent in superficial form and immanent for other forms so if we speak “onycholysis” we speak “onychomycosis”, with no need to repeat; other nail signs.