Nails: Anatomy, Filing Technique and Nail Disorders
The Nails domain tests nail anatomy, growth, manicure and pedicure technique, filing, equipment hygiene and the recognition of nail disorders that must be referred rather than treated. Questions commonly present a visual description of a nail and ask what it is, whether you can treat it, and what you do next.
Anatomy you must be able to label
- Nail plate: the visible keratin structure, roughly 100 layers thick, pH around 5.5.
- Nail bed: vascular tissue beneath the plate; its colour shows through as pink.
- Matrix: generates the plate; injury here causes permanent ridging or distortion.
- Lunula: the pale half-moon, the visible distal portion of the matrix.
- Eponychium: living tissue at the base; the cuticle is the dead keratinised layer on the plate - never cut the eponychium.
- Hyponychium: the seal under the free edge, a key barrier against infection.
Growth and filing rules
- Fingernails grow about 3 mm per month; toenails about 1 mm. A fingernail replaces in 4–6 months, a toenail in 12–18 months.
- File natural nails in one direction with a fine-grit file; sawing and coarse grits delaminate the plate and cause splitting.
- Keep side walls intact; over-filing narrows the plate and invites ingrowing toenails.
- Prolonged soaking softens keratin and leaves the plate flexible and prone to tearing - limit soak time.
Worked example
A pedicure client has a green-black discolouration under the free edge of the big toe, and the nail plate is lifting. Reasoning: this suggests a bacterial or fungal infection with possible onycholysis. It is a contra-indication to cosmetic pedicure on that nail. Correct action: do not soak, file or apply polish; explain the finding, advise referral to a GP or podiatrist, and treat the other nails only with client consent. Record the observation.
Traps that cost marks
- Cutting the cuticle instead of softening and pushing back the eponychium.
- Calling onycholysis a cosmetic problem when it requires referral.
- Reusing files or nippers without disinfection.
- Confusing paronychia (inflamed nail fold) with onychomycosis (fungal plate infection).