This document provides an overview of nail anatomy through a presentation. It discusses the basic structure of the nail including the nail matrix, nail bed, nail plate, cuticle, and lunula. It describes the blood supply and nerve innervation of the nail. It also reviews nail growth and factors that can affect the rate of growth such as age, gender, season, and certain medical conditions. The presentation provides details on nail development during embryology and changes that occur in childhood and old age.

1. TUTORIAL PRESENTATION
ANATOMY OF NAIL
MODERA
TOR Dr. Ram Singh Meena Sir
PRESENTER-Dr Mehul Choudhary

2. INTRODUCTION
🞭 Nail apparatus - strong, relatively
inflexible, keratinous.
🞭 Protective covering for fingertip.
🞭 Allows precision and delicacy when picking up
small objects.

3. SHORT EMBRYOLOGY
🞭 Primitive epidermis – 9 - 20th wks.
🞭 20 wk:
🞭 Matrix cells show postnatal-type cell division
differentiation and keratinization.
🞭 Nail bed loses its granular layer at this stage.
🞭 36 wk: Nail plate reaches the tip of the digit.

4. NAIL BASIC STRUCTURE
🞭 1/4 nail is covered by the proximal nail fold.
🞭 Lunula (half-moon, lunule):
🞭 Under proximal part of nail
🞭 Most distal region of the matrix
🞭 Nail plate usually appears pink, due to its
translucency, which allows the redness of the
vascular nail bed to be seen through it.

5. NAIL BASIC STRUCTURE
🞭 HYPONYCHIUM - Epithelium beneath nail plate at
junction of distal nail edge and skin.
🞭 EPONYCHIUM - Small band of epithelium from posterior
nail wall onto nail base.

6. 🞭 PROXIMAL NAIL FOLD
🞭 LATERAL NAIL FOLDS
🞭 THE MATRIX
🞭 subdivided into dorsal, intermediate and ventral sections.

7. ANATOMY
🞭 NAIL FOLDS
🞭 The proximal and lateral nail folds are similar in
structure to the adjacent skin and devoid of
dermatoglyphic markings.
🞭 From the distal area of the proximal nail fold the
cuticle adheres to the upper surface of the nail
plate.
🞭 It serves to protect the structures at the base of
the nail from environmental insults.

8. 🞭 NAIL MATRIX
🞭 Nail matrix produces the nail plate.
🞭 The nail matrix contains melanocytes which
donate pigment to the keratinocytes.
🞭 there is presence of 6.5 melanocytes per
millimetre of matrix basement
membrane.
🞭 Langerhans cells are detectable in the matrix by
CD1a staining.

9. 🞭 NAIL BED
🞭 Nail bed consists of epidermis with underlying
connective tissue closely apposed to the periosteum
of the distal phalanx.
🞭 Within the connective tissue network lie blood
vessels,lymphatics,network of elastic fibre and fat
cells.At the distal margin, eccrine sweat glands
have been seen.

10. 🞭 NAIL PLATE
🞭 The nail plate comprises three horizontal layers: a
thin dorsal lamina, the thicker intermediate lamina
and a ventral layer from the nail bed.
🞭 The nail plate contains significant amounts of
phospholipid which contributes to its
flexibility.
🞭 The nail plate is also rich in calcium, found as
the phosphate in hydroxyapatite crystals.

11. 🞭 NAIL KERATIN
🞭 Normal nail demonstrates that the suprabasal keratin
pair K1/K10 is found on proximal nail fold.
🞭The nail bed contains keratin synthesized in normal
basal layer epithelium, K5/K14, which is also found
in nail matrix.
🞭 Keratin pair K6/K16 are present in the nail bed but
not in the germinal matrix.

12. BLOOD SUPPLY OF NAIL
🞭 Blood supply to the nail bed and matrix derived from
paired digital arteries, a large palmar and small dorsal
digital artery on either side.
🞭 There are two main arterial arches (proximal and distal)
supplying the nail bed and matrix, formed from
anastomoses of the branches of the digital arteries.
Arterial supply of the distal finger.

13. BLOOD SUPPLY OF NAIL
• 🞭 Within the matrix, vessels are longitudinal with a
helicoidal twisting.
• 🞭 There are many arteriovenous anastomoses
beneath the nail— Glomus bodies—which are
concerned with heat regulation.
• 🞭 Glomus bodies are important in maintaining acral
circulation under cold conditions: arterioles constrict with
cold but glomus bodies dilate.

14. Nerve supply of Nail
• UPPER LIMB - The nerve supply to the nail bed is from
the median and ulnar digital nerves, which parallel the
course of the arterial supply to the nail bed

15. Nerve supply of Nail
• LOWER LIMB- The nerve supply to the nail bed is from
the superficial and deep fibular nerve.

16. NAILGROWTHAND
MORPHOLOGY
• 🞭 Cell kinetics
• 🞭 Measured by
• Immunohistochemistry, autoradiography and direct
measurement of matrix product by ultrasound
,micrometer or histology.
• 🞭 The rate of nail growth is about 3 mm/month for
finger nails and about 1 mm/month for toe nails.

17. MORPHOLOGY
🞭 The factors responsible to produce
a relatively flat nail plate are
🞭 orientation of the matrix rete pegs and papillae.
🞭 the direction of cell differentiation and moulding of
nail growth between the proximal nail fold and
distal phalanx.
🞭 Containment laterally within the lateral nail folds.
🞭 the adherent nature of the nail bed

18. Chemical Properties of
the Nail Plate
• The nail plate, consists mainly of fibrillar, low-sulfur
protein, globular, high-sulphur matrix protein; and high
glycinetyrosine rich matrix protein.

19. NAILS IN CHILDHOOD
• 🞭 In early childhood, the nail plate is relatively thin and
may show temporary koilonychia.
• 🞭 Nails are also prone to terminal onychoschizia most
prominent on the sucked thumb.
• 🞭 A herringbone pattern is common in children and
gradually diminishes with time, reflecting a gradual
matrix maturation.

20. NAILS IN OLDAGE
• 🞭 The subungual area in old age may show thickening of
blood vessel walls with vascular elastic tissue
fragmentation.
• 🞭 The nail plate becomes pallor, dull and opaque
with advancing years.
• 🞭 White nails similar to those seen in cirrhosis, uraemia
and hypoalbuminaemia may be seen.

21. PHYSIOLOGICAL AND ENVIRONMENTAL
FACTORS AFFECTING THE RATE OF NAIL
GROWTH.
FASTER SLOWER
DAYTIME NIGHT
RIGHT HAND NAILS LEFT HAND NAILS
YOUTH,INCREASINGAGE OLD AGE
FINGERS TOESAND THUMBS
MALE GENDER FEMALE
SUMMER WINTER

22. PATHOLOGICAL FACTORS AFFECTING THE RATE
OF NAIL GROWTH
FASTER SLOWER
IDIOPATHIC FINGER IMMOBILIZATION
PSORIASIS FEVER
HYPERTHYRODISM HYPOTHYRODISM
ARTERIOVENOUS
SHUNTS
BEAU’S LINES
POOR NUTRITION