The commonest form of onychia has already been referred to with whitlow.
Back pressure upon the matrix from a short shoe upon a thick unresisting nail, is frequently the cause of onychia.
Paronychium-ia: one or more bristle-like appendages of onychia; q.v.
onychia is the term applied to an infection of the soft parts around the nail or of the matrix beneath it.
onychia o·nych·i·a (ō-nĭk'ē-ə)
Inflammation of the fingernail or toenail matrix. Also called onychitis.