TUTORIAL NAIL.pptx

anatomy and function of nails

1. TUTORIAL PRESENTATION AN A T OMY OF NAIL MODER A T OR D r . R am S ingh M eena Sir PRESENTER - Dr Mehul Choudhary

2. INT R O D UCTI O N 🞭 N ail apparatus - strong, relatively inflexible, keratinous . 🞭 P rotective covering for fingertip . 🞭 Al lows precision and delicacy when picking up small objects .

3. SHORT EMBRYOLOGY 🞭 P rimitive epidermis – 9 - 20th wks. 🞭 20 wk : 🞤 M atrix cells show postnatal-type cell division d ifferentiation and keratinization . 🞤 N ail bed loses its granular layer at this stage. 🞭 36 wk : N ail 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 🞤 M ost distal region of the matrix 🞭 N ail 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 - E pithelium beneath nail plate at junction of distal nail edge and skin. 🞭 EPONYCHIUM - S mall 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 s erves 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 .A t 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 🞤 N ormal 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. 🞤 K eratin pair K6/K16 are present in the nail bed but not in the germinal matrix .

12. BLOOD SUPPLY OF NAIL 🞭 B lood 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. N A IL G R O W T H A ND M OR P HO L O G Y 🞭 Cell kinetics 🞤 Measured by I mmunohistochemistry , 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. N A I L S IN C H I L D H OOD 🞭 In early childhood, the nail plate is relatively thin and may show temporary koilonychia . 🞭 N ails 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. N A I L S IN O L D A G E 🞭 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. 🞭 W hite 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 YOU T H,INC R EASING AGE OLD AGE FINGERS T OES AND T H U MBS MALE GENDER FEMALE SUMMER WINTER

22. PATHOLOGICAL FACTORS AFFECTING THE RATE OF NAIL GROWTH FASTER SLOWER IDIOPATHIC FINGER IMMOBILIZATION PSORIASIS FEVER HYPERTHYRODISM HYPOTHYRODISM A R T ERIOVENOUS SHUNTS BEAU’S LINES POOR NUTRITION