N
N-A dressing non-adherent wound dressing (see Table D10)
naevus benign, localized, overgrowth of skin melanocytes or blood vessels (see ABCDE)
naevus spilus; speckled lentiginous naevus small light brown macule, increasing in size over time to form a speckled benign lesion of up to 10 cm diameter; it should be monitored as it may undergo malignant changes (see ABCDE)
vascular naevus; port-wine stain congenital, often widespread, red/purple discoloration of skin, caused by capillary hypertrophy
nail (1) steel rod; used to approximate and fixate fractured bone ends
nail (2) the continuously growing, flexible, keratin plate at the dorsal aspect of the tip of a digit; Figure N1; see onych-; subungual
black nails dark or brown-black discoloration of the nail plate/s; caused by chronic Pseudomonas infection (e.g. chronic paronychia), chronic subungual haemorrhage (e.g. due to repeated local trauma), psoralens and long-wave ultraviolet A light (PUVA) therapy, systemic chemotherapy or radiotherapy; longitudinal pigmented bands are common in black races but rare in Caucasians; dark or irregular longitudinal bands in Caucasians should undergo biopsy (to exclude malignancy)
brittle nails common condition, e.g. in middle-aged women, characterized by lamellar splits, associated with repeated immersion in detergent water
half-and-half nails white coloration of proximal half of nail plate and pink-brown coloration of distal half; associated with uraemia, chemotherapy, human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), old age
ingrowing nail; onychocryptosis penetration of nail sulcus by nail spicule or outer margin of nail plate, with associated local tenderness, swelling, pain, inflammation, infection (paronychia) and granuloma (hypergranulation) formation; most commonly affects hallux nail, often in adolescent males (see Table I6)
involuted nail; pincer nail; omega nail exaggerated transverse curvature of nail plate; outer borders are deeply embedded within and obscured by surrounding soft tissues; prone to onychocryptosis and onychophosis
nail thickening hypertrophy and overgrowth of nail plate, with or without distortion; indicative of previous nail trauma (i.e. one severe blow, or repeated/chronic minor trauma), fungal infection or skin disease (e.g. psoriasis, pachyderma congenita); see onychauxis; onychogryphosis; onychomycosis
nails in alopecia areata linear pattern of very fine pits of nail plate and stippling/redness of lunulae, due to autoimmune changes in patients with, or who will develop, alopecia areata
nails in chemotherapy nail dystrophy, hyperpigmentation and infection due to systemic effects of chemotherapy, e.g. transverse white bands (each band representing one chemotherapy cycle), Beau’s line formation, nail loss (due to drug effect on nail keratinocytes), diffuse or banded (transverse or longitudinal) hyperpigmentation (due to nail bed melanocyte overactivity), subungual haemorrhages (due to overreaction to local trauma) and acute paronychia and/onychomycosis (due to drug-related immunosuppression)
nails in Darier’s disease small ‘notch’ at free margin of affected nail + local subungual hyperkeratosis, linked to single/multiple longitudinal red streaks in nail, extending from free margin to eponychium
nails in dermatomyositis e.g. pterygium inversus unguis formation, eponychial ‘fraying’, inflammation and swelling of proximal nail folds, local telangiectasia, and dilated and tortuous capillaries of dorsal nail fold; reflecting earlier active periods of dermatomyositis
nails in lichen planus e.g. plate thinning, irregularity and longitudinal ridging, onycholysis, pterygium formation, twenty-nail dystrophy and/or anonychia (due to scarring of the nail matrix); noted in 10% of patients with lichen planus
nails in pityriasis rubra pilaris thickening and onycholysis with severe subungual hyperkeratosis and nail splinters
nails in psoriasis generalised dystrophy due to effects of psoriatic lesions within elements of nail apparatus (i.e.: nail bed, matrix plate), e.g.: onychauxis, central, distal or total onycholysis, chromonychia, paronychia, pronounced nail plate ridging (trachyonychia); thimble pitting, oil spot sign and pustular atrophy of nail bed (acrodermatitis continua of Hallopeau)
nails in Reiter’s disease psoriatic-like changes, with nail tenderness, marked pitting, subungual pustule formation and periungual psoriasis-like lesions
nails in scleroderma e.g. micro-nychia, thin and flattened nail plates, marked (longitudinal/transverse) distal nail plate overcurvature, pterygium inversus unguis, and increased distal overgrowth of eponychium
nails in systemic lupus erythematosus and mixed connective tissue disease e.g. onycholysis, red lunulae, pterygium inversus unguis, severe nail dystrophy with deep longitudinal nail furrows (secondary to matrix scarring) and similar nail effects in dermatomyositis
nails in tuberose sclerosis isolated or multiple garlic clove fibromas (Koenen’s tumours) growing out from proximal nail folds; overlie/distort the local nail plate
ostler’s nail; ram’s horn nail gross nail plate thickening (onychauxis), distortion (onychogryphosis) and overcurvature; caused by trauma-related scarring of nail matrix, e.g. subsequent to dropping a heavy object on the toe and matrix area
pincer nail; trumpet nail increased transverse overcurvature of distal one-third of nail plate; lateral nail edges converge distally and traumatize/perforate medial and lateral nail folds; distal one-third of nail may form a cylinder and strangulate entrapped nail bed soft tissues in extreme cases
plicatured nail; tile nail lateral nail involution, i.e. normal central transverse curvature of main plate, but exaggerated curvature at lateral margins; nail plate edges are deeply embedded within nail sulci
red nails; red lunulae red-purple discoloration of proximal nail and hyperaemia of local nail bed; associated with e.g. systemic lupus erythematosus, alopecia areata and some drug therapies
retinoid nails e.g. thinning and brittleness of entire nail plate, transverse ridging and white banding, Beau’s lines, onychomadesis, acute paronychia; secondary to systemic retinoids (i.e. synthetic vitamin A analogues)
scroll nail inward curvature of outer border/s of nail plate (toward midline of toe) with entrapment of local soft tissues; an exaggerated form of involuted nail
spoon nail; koilonychia lateral/medial nail border elevation and central depression (concavity) of nail plate; associated with iron-deficiency anaemia, malnutrition, thyrotoxicosis, Raynaud’s and scleroderma; note: may be normal in toddlers
terry nails thin, brittle, lustreless nails with marked longitudinal ridging/beading, narrow, transverse, red-brown band (just proximal to free margin); characteristic of old age
yellow nails yellowing of nail plate; with increased mediolateral/proximodistal curvature and loss of eponychial tissue; secondary to virtual cessation of linear nail growth but marked smooth thickening of nail plate; of obscure cause, but associated with underlying disease states, e.g. pulmonary tuberculosis
nail avulsion removal of all or part of a nail plate with or without associated matrisectomy
chemical nail avulsion application of 40% urea cream to hypertrophied nail tissue, over several weeks; 40% urea causes marked maceration of nail keratin, and gradual plate erosion
surgical nail avulsion removal of all or part of nail plate (by its separation from local soft-tissue attachments [i.e. proximal nail fold and eponychium; lateral/medial nail folds; nail bed], and sharp division of nail segment from remaining main plate) with or without matrisectomy, to relieve symptoms of ingrowing toenail, pain due to nail malformation or severe onychophosis
traumatic nail avulsion unplanned plate avulsion due to application of sudden force/trauma; subsequent nail growth is likely to be dystrophic
nail conditions nail conditions that respond to topical medicaments, see Table N1
Table N1 Nail conditions that respond to topical medicaments
| Nail condition | Topical medicament |
|---|---|
| Thickened nail plate | Softened with: Keratolytics, e.g. 40% urea cream, 12% salicylic acid in collodion Emollients, e.g. lanolin |
| Onychophosis or impacted debris in the nail sulcus | Revealed by industrial methylated spirit (IMS) or isopropyl alcohol flooded into sulcus Softened by 10 vol hydrogen peroxide, left in situ for 10 minutes |
| Relaxed, rubbery or soft nail sulcus | Astringents, e.g. 20% silver nitrate solution, weak ferric chloride solution, 3% salicylic acid in IMS, 10% formalin solution |
| Inflamed sulcus | Hamamelis water, Burow’s solution |
| Hypergranulation tissue | Application of astringents, e.g. 50% silver nitrate solution, strong ferric chloride solution, 80% (liquefied) phenol for 1 minute, followed by IMS lavage |
nail field; fetal nail field dorsal depression at tip of terminal phalanx, preceding nail formation
nail matrix transverse, fold-like invagination of embryonic ectoderm at dorsal aspects of digital termini; differentiates into keratinocytes, which undergo enzymic degradation to form nail plate; dorsal matrix forms dorsal nail plate; most distal area of ventral matrix forms ventral nail plate; remainder of matrix forms intermediate nail plate; distal limit of matrix is visible (through nail plate) as distal limit of lunula
nail–patella syndrome see syndrome, nail–patella
nail plate keratin plate (formed as dorsal, intermediate and ventral nail plates – see nail matrix) investing dorsal aspects of termini of all digits; nail plates grow throughout life
nail surgery see nail avulsion
National Research Register; NRR UK national resource holding information on all current funded NHS-based research
natural gait barefoot gait (shoewear should allow the foot and limb to function as in barefoot gait)
navicular drop decrease in the distance between the inferior aspect of navicular and the plantar plane (support surface) in a non-weight-bearing foot and weight-bearing foot (see navicular height)
needle surgical device used to puncture tissues
hypodermic needle fine hollow tube, with a cutting tip, used to access subdermal tissues; used in conjunction with a syringe to administer fluid agents (e.g. local anaesthetic), collect blood or aspirate fluids
suture needle straight or curved needle (round or triangular [reverse cutting or cutting] in cross-section) carrying the suture thread
needle holder small surgical forceps with locking handles; used to carry a suture needle
negative casting; negative mould mould of foot/part of foot, formed using low-loss plaster of Paris (PoP) bandage, dental impression material, casting foam or putty, from which a positive cast is made (Box N1)
