Chapter 89

Question 1

Four Components of the Nail Apparatus

Answer 1

• proximal nail fold
• nail matrix
• nail bed
• hyponychium

Question 2

What determines the shape and transverse curvature of the nail?

Answer 2

The shape of distal phalangeal bone above

Question 3

Functions of the Fingernails

Answer 3

1. aesthetics
2. protection of distal phalanges
3. enhanced tactile discrimination
4. aid in grabbing small objects
5. scratching and grooming

Question 4

Functions of the Toenails

Answer 4

1. protects distal phalanges

2. contrubute to pedal biomechanics

Question 5

the most distant portion of the firm attachment of nail plate to nail bed

Answer 5

onychocorneal band

• important anatomic barrier against environmental hazards

Question 6

other name for onychocorneal band

Answer 6

nail isthmus

Question 7

pink band that separates the nail

isthmus from the white free edge of of the nail plate by 1.0-1.5mm

Answer 7

onychodermal band

Question 8

found at the tip of the digit where the nail plate separates from the underlying tissues

Answer 8

hyponychium

Question 9

three portions of the nail plate

Answer 9

1. dorsal nail plate
2. intermediate
3. ventral plate

Question 10

which is responsible for the production of dorsal and intermediate nail plate

Answer 10

nail matrix

Question 11

which is responsible for the production of ventral nail plate

Answer 11

nail bed

Question 12

ventral nail plate is missing in what portion of the nail plate

Answer 12

above the lunula

Question 13

what marks the separation of the nail fold from the matrix

Answer 13

absence of granular layer

Question 14

horny portion of the nail fold

Answer 14

cuticle

• prevents separation of nail
  plate from the nail fold

Question 15

persistence of nuclear fragments within intermediate nail plate

Answer 15

leukonychia spots

Question 16

Why is the LUNULA white?

Answer 16

1) light diffraction due to the nuclear fragments

2) nail matrix capillaries are less visible than nail bed capillaries

Question 17

unique keratinization pattern of the nail isthmus

Answer 17

onycholemmal keratinization

Question 18

normal water content of nail plate

Answer 18

18-30%

less than 18% brittle nails
more than 30% opaque and soft nails

Question 19

fingernail with slowest growth

Answer 19

fifth digit

Question 20

toenail with fastest growth

Answer 20

big toe

Question 21

deep and irregularly distributed nail pits

Answer 21

psoriasis

atopic dermatitis

Question 22

superficial and geometric nail pitting

Answer 22

alopecia areata

Question 23

onychorrhexis

Answer 23

lichen planus