Nail Technology
Anatomy of the nail unit
The nail plate is the visible hard keratin; it rests on the nail bed. The matrix extends beneath the proximal fold and produces the plate - permanent ridges, thinning, or distortion follow matrix damage, which is why questions about irreversible nail injury point to the matrix, not the plate. The lunula is simply the visible portion of the matrix. The eponychium is living skin at the base; the cuticle is the dead tissue that sheds there. The hyponychium seals under the free edge, and the nail folds (sidewalls) frame the sides.
Growth and disorders
Fingernails grow roughly 0.1 mm per day and take about three to six months to replace; toenails grow about half that rate. Refer rather than treat: onychomycosis (tinea unguium), paronychia (bacterial infection of the fold), onycholysis, severe onychorrhexis, and any discharge or inflammation. Leukonychia (white spots) and Beau's lines are usually cosmetic history markers.
Services and product chemistry
Manicures and pedicures follow a fixed order: sanitize hands and your own, assess, shape, soak, treat the cuticle gently, massage, polish. Never cut living tissue or use credo blades; nippers are for a true hangnail only. Acrylics combine a liquid monomer with a powder polymer. Files, buffers, and porous items cannot be disinfected - use them once, then discard or give them to the client.
Worked example
A diabetic client asks for a pedicure. Diabetes affects circulation and healing, so the conservative, correct response is to require physician clearance before soaking, filing, or nipping, and to skip aggressive cuticle work entirely.