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Ebopras > The Perionychium > Flashcards

The Perionychium Flashcards

1
Q

Name the labeled structures in Figure 37-1:

A

…

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2
Q

What is the Perionychium?

A

The nail bed (composed of the sterile and germinal matrix) and surrounding soft tissues (paronychium).

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3
Q

What is the hyponychium?

A

The junction of the nail bed (sterile matrix) and the fingertip skin, beneath the distal free margin of the nail. It consists of a keratinous plug that prevents debris from getting under the nail plate. The hyponychium also contains large numbers of leukocytes and lymphocytes and is the first barrier of defense to prevent bacteria and fungi from invading the subungual area.

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4
Q

What is the eponychium?

A

The distal portion of the nail fold where it attaches to the surface of the nail.

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5
Q

What is the paronychium?

A

Soft tissue around the nail and the nail folds comprises the paronychium.

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6
Q

What is the nail bed?

A

The nail bed consists of (a) the germinal matrix on the proximal ventral floor of the nail fold and (b) the sterile
matrix extending from the lunula to the hyponychium

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7
Q

What is the germinal matrix?

A

The germinal matrix comprises the ventral floor of the nail fold. Highly vascular and composed of germinal cells near the periosteum, the germinal matrix produces 90% of the nail volume. As the germinal cells duplicate, previously formed cells are forced toward the nail and the pressure causes the cells to flatten, elongate, and stream distally into the nail.

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8
Q

What is the sterile matrix?

A

Part of the nail bed that extends from the lunula to the hyponychium.

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9
Q

What is the nail fold? Why is it important?

A

The nail fold houses the proximal nail plate and is composed of the germinal matrix on the ventral floor and the portion of the nail bed that forms the cells which makes the nail shine on the dorsal roof. The patency of the nail fold is crucial for normal nail growth; hence, either the nail plate or a temporary stent should be placed to keep the nail fold open.

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10
Q

What is the lunula?

A

The curved white opacity representing the visible, distal portion of the germinal matrix

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11
Q

What is the nerve supply to the perionychium?

A

Dorsal branches from the volar digital nerves.

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12
Q

What is the arterial supply to the nail?

A

Two dorsal branches of the volar digital arteries.

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13
Q

What makes up the nail plate?

A

Flattened sheets of anuclear keratinized epithelium densely adherent to one another.

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14
Q

What changes occur in the nail plate distal to the lunula?

A

The cell nuclei degenerate distal to the lunula. This is the junction of the sterile and germinal matrix.

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15
Q

What lies beneath the sterile matrix?

A

Periosteum of the distal phalanx; hence fracture of the distal phalanx is associated with a high incidence of nail bed
injury.

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16
Q

What produces the nail plate?

A

The germinal matrix produces 90% of the nail plate volume.

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17
Q

What contributes to nail plate adherence?

A

The sterile matrix produces keratin, which thickens the nail and allows adherence of the nail plate to the bed as it
migrates distally.

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18
Q

What contributes to the smooth shiny surface of the nail plate?

A

The dorsal roof of the nail fold.

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19
Q

How is the nail produced?

A

The nail plate is a multilayered stacked sheet of cornified cells derived from anucleate onychocytes that arise from
the germinal matrix epithelium of the nail bed.
The epithelium of the germinal matrix, sterile matrix, and eponychial fold contributes to the production of the nail plate through three modes of keratinization.
The germinal matrix epithelium undergoes onychokeratinization, forming the main substance of the hardened nail plate, which is composed of stratified layers of cornified onychocytes.
The sterile matrix epithelium produces a semirigid keratin through a process known as onycholemmal keratinization. This semirigid keratin increases the overall thickness of the nail and also acts as superglue adhesive for the nail plate to maintain its adherence to the nail bed.
The eponychial fold (dorsal roof ) is responsible for the external sheen of the healthy nail plate by epidermoid keratinization. The cuticle, hyponychium, and lateral nail folds also contribute, in a minor degree, to the surface epidermoid keratinization of the nail plate

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20
Q

Name five functions of the fingernail.

A
  1. protection of the fingertip
  2. improved pulp tactile sensation through provision of counterforce to the pulp 3. assistance in picking up objects
  3. self-defense (scratching)
  4. regulation of peripheral circulation
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21
Q

What area of the body has the highest concentration of lymphatics?

A

The hyponychium.

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22
Q

What is the composition of the hyponychium?

A

It is a mass of keratin with a large population of lymphocytes and polymorphonuclear leukocytes.

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23
Q

Purpose of the hyponychium?

A

Barrier to infection.

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24
Q

At what rate does the nail grow?

A

An average of 0.1 mm/day or 100 days for complete nail growth; however, after an injury distal growth is halted for
21 days as the proximal nail thickens.

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25
Q

❍ What is clubbing?

A

Exaggerated convex curvature of the nail plate.

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26
Q

What conditions are thought to cause clubbing?

A

r familial clubbing (idiopathic)
r pulmonary disease—pulmonary fibrosis, sarcoidosis, cystic fibrosis
r cardiac disease—cyanotic congenital heart disease, bacterial endocarditis r gastrointestinal disease—ulcerative colitis, Crohn’s disease, liver cirrhosis r cancer—thyroid, thymus, disseminated chronic myelogenous leukemia r other—acromegaly, pregnancy

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27
Q

What is chromonychia?

A

Changes in nail color.

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28
Q

What causes this?

A

Chromonychia can be induced by renal failure, subungual hemorrhage, or medications. Antineoplastic drugs frequently cause melanonychia. Drugs most commonly involved are adriamycin, cyclophosphamide, and vincristine. Chromonychia is also associated with AIDS.

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29
Q

what is onycholysis?

A

Premature separation of the nail bed and nail plate.

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30
Q

What causes onycholysis?

A

Abnormalities of the sterile matrix, often secondary to posttraumatic scarring.

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31
Q

What medications are strongly associated with onycholysis?

A

Taxane chemotherapeutics including paclitaxel and docetaxel.

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32
Q

What causes longitudinal splitting of the nail plate?

A

Abnormalities of the germinal matrix (ventral nail fold), often secondary to posttraumatic scarring between the nail
roof and nail floor.

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33
Q

What causes longitudinal grooving in the nail plate?

A

Abnormalities of the nail fold (tumor, bony change, or posttraumatic deformities).

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34
Q

What are nail spikes or remnants?

A

Small, often painful, volumes of nail plate that grow through the overlying skin. These usually occur after
incomplete removal of the nail matrix following fingertip amputations.

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35
Q

How are these treated? (grooving)

A

Definitive excision.

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36
Q

Which is the most commonly injured fingernail?

A

The long finger followed, in order of descending length, by the ring, index, small, and thumb.

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37
Q

What is the most common mechanism of injury?

A

Doors.

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38
Q

What is the significance of a subungual hematoma?

A

There is an underlying nail bed injury.

39
Q

How are these treated?

A

Trephination if the hematoma covers less than 50% of the nail plate. Removal of the nail plate and direct repair of
the nail bed is required if the hematoma is more than 50% of the nail plate.

40
Q

What is trephination?

A

Creation of a hole in the nail plate to allow drainage of the hematoma, done with a large bore needle. The nail plate
should be surgically scrubbed prior to trephination to avoid infection.

41
Q

When should nail bed injuries be treated and why?

A

Acutely because secondary repair will rarely provide satisfactory results.

42
Q

Key steps in nail bed repair (to be carried out under loupe magnification):

A
  1. Adequate anesthesia to the finger in the form of a digital block.
  2. Use of digital tourniquet for optimal visualization.
  3. Careful removal of the nail plate using sharp scissors or a periosteal elevator to prevent further iatrogenic injury to nail bed.
  4. Repair of laceration using fine absorbable suture such as 6–0 chromic.
  5. Replacement of nail plate, or if absent, placement of a substitute material to protect the repair and maintain the
    nail fold.
  6. Alignment and approximation of lacerated edges to avoid ridging.
43
Q

Do you need an X-ray of the fingertip?

A

Yes, to evaluate the distal phalanx.

44
Q

What percent of nail bed injuries are associated with a distal phalanx fracture?

A

50.

45
Q

How are nondisplaced fractures treated?

A

Repair the nail bed if necessary and replace the nail plate, to act as a splint.

46
Q

How are unstable displaced fractures treated?

A

Fracture reduction, bony fixation with crossed K-wires, repair of the nail bed, and replacement of the nail plate.

47
Q

What is the treatment for an avulsed nail plate?

A

Find the nail plate, replace it with any attached portions of sterile matrix. If this is not available, splint the nail fold
open with a piece of Adaptic, the back of a suture pack, or portion of a Penrose drain.

48
Q

After nail plate removal, why is it important to replace the nail plate (or use a substitute replacement)?

A

To splint the repair and prevent scarring between the roof and floor of the nail fold.

49
Q

With severe crush injuries, what is done with the nail bed tissue attached to the nail plate after the nail plate is removed?

A

Replaced onto the nail bed as free grafts.

50
Q

When are split-free nail bed grafts used?

A

To replace large defects in the nail bed.

51
Q

Where is a split-free nail bed graft harvested from?

A

Ideally from an undamaged area on the injured finger or from an amputated digit

52
Q

What is alternative source for split nail bed grafts?

A

The great toe.

53
Q

what is a hook nail deformity?

A

nail that curves volar sharply at the finger tip

54
Q

what causes hook nail?

A

Inadequate tip support, usually due to traumatic loss of bone.

55
Q

What is Pincer nail deformity?

A

Referred to as omega nail deformity or trumpet nail deformity, it is a relatively rare condition in which there is a transverse overcurvature of the nail plate

56
Q

pincer nail ethiology?

A

The exact etiology is obscure, but a loss of the lateral integrity of the distal phalanx may occur, allowing a greater
curvature of the nail plate.

57
Q

pincer naik treatment?

A

Restoration of the normal contour and shape of the nail plate is achieved with the aid of dermal grafts under the
lateral edges of the nail bed.

58
Q

What causes nail ridges?

A

Scar beneath the nail bed or an irregularly healed distal phalanx fracture.

59
Q

nail ridges treatment?

A

Excision of the scar and/or smoothing out of the irregularity.

60
Q

What causes a split nail deformity?

A

A ridge or longitudinal scar in the germinal matrix.

61
Q

split nail treatment?

A

Resection of the scar and replacement with a FULL-thickness germinal matrix graft (typically from the second toe).

62
Q

What causes nonadherence of the nail plate?

A

A transverse scar in the sterile matrix.

63
Q

nonadherence nail plate treatment?

A

Scar resection and replacement with a split-thickness sterile matrix graft.

64
Q

What are nail cysts or nail spikes?

A

A spike of nail plate growing out from an amputation stump.

65
Q

what causes nail cysts?

A

Failure to remove all of the germinal matrix from the nail fold when performing an amputation at the proximal portion of the distal phalanx.

66
Q

nail cyst treatment?

A

Complete resection of the nail cyst and its wall.

67
Q

What is an acute paronychia?

A

Infection of the skin surrounding the nail plate.

68
Q

paronychia most common cause?

A

Staphylococcus aureus infection.

69
Q

acute paronychia treatment?

A

Drainage with or without partial nail plate removal.

70
Q

What is chronic paronychia?

A

Chronic paronychia is characterized by persistent, indurated infections of the eponychium, typically seen in people whose hands are chronically exposed to water with detergents and alkali, such as cleaning workers, bartenders, and kitchen staff. The etiology is thought to be initial bacterial infection, typically followed by superinfection and colonization of the eponychium with a fungus such as Candida albicans.

71
Q

chronic paronychia treatment?

A

Systemic antifungals or antibiotics with or without nail plate removal. Eponychial marsupialization has been
described and has been highly effective at clearing persistent infections.

72
Q

What is onychomycosis?

A

Chronic fungal infections of the nail.

73
Q

onychomycosis PRESENT?

A

Nail plate discoloration, thickening, and onycholysis.

74
Q

onychomycosis treatment?

A

Topical antifungals alone are typically unsuccessful. Topical antifungal with nail plate removal or systemic
antifungal is recommended.

75
Q

What is the most common cause of paronychial infections?

A

Chronic fungal infections.

76
Q

What is the most common bacterial infection of the nail?

A

S aureus paronychium.

77
Q

bacterial infection of the nail treatment?

A

Drain any abscesses by lifting the paronychium with or without partial nail plate removal using a number 11 or 15 blade, followed by soapy water soaks 3 to 4 times a day.

78
Q

What is herpetic whitlow?

A

Self-limited viral infection of the fingertips caused by the herpes simplex virus. It is transmitted by skin-to-skin contact and is often seen in medical and dental personnel, as well as in children. Herpetic whitlow may also present with swelling and erythema, though typically patients have disproportionately greater pain than in the case of bacterial infections. Vesicles are also seen, containing fluid that may be clear or turbid, but is never purulent.

79
Q

How do you diagnose herpetic whitlow?

A

The diagnosis is usually made clinically, though it is possible to confirm it by use of a Tzanck preparation or viral culture. It is important to distinguish herpetic whitlow from bacterial infections, as a surgical incision for the former can lead to complications involving the entire digit or systemic spread, and is contraindicated.

80
Q

How do you treat herpetic whitlow?

A

Herpetic whitlow should generally be treated conservatively and typically runs a self-limited course of
approximately 21 days. Treatment most often is directed toward symptomatic relief.
In primary infections, topical acyclovir 5% has been demonstrated to shorten the duration of symptoms and viral shedding. Oral acyclovir may prevent recurrence. Doses of 800 mg twice daily initiated during the prodrome may abort the recurrence. Antibiotic treatment should only be used in cases complicated by bacterial superinfection.
Tense vesicles may be unroofed to help ameliorate pain.

81
Q

Name three common benign periungual tumors.

A

Mucous cyst, glomus tumor, and pyogenic granuloma.

82
Q

What is a mucous cyst?

A

A dorsal ganglion of the DIP, they are usually associated with an osteophyte.

83
Q

mucous cyst present?

A

Dorsal swelling of the DIP with or without longitudinal grooving of the nail plate.

84
Q

mucous cyst treatment?

A

Excision of the ganglion and removal of the osteophyte.

85
Q

What is the key to the treatment of a mucous cyst?

A

Removal of the osteophyte.

86
Q

How do glomus tumors present?

A

These are 1 to 2 mm in size and have a classic triad of tenderness, pain, and cold sensitivity.

87
Q

glomus diagnose?

A

MRI.

88
Q

glomus treatment?

A

Resection with an approach that includes removal of the nail plate.

89
Q

What is a pyogenic granuloma?

A

Exuberant mass of granulation tissue that forms after a relatively minor trauma.

90
Q

pyogenic granuloma treatment?

A

Complete excision through curettage or ablation with silver nitrate sticks. Incomplete excision will lead to
recurrence.

91
Q

Differential diagnosis of a pigmented subungual lesion?

A

Posttraumatic hemorrhage (most common), benign nevus, subungual melanoma.

92
Q

What is the differential diagnosis of pigment deposition within the nail plate?

A

Melanonychia striate longitudinalis (benign lesions common in black patients), a benign subungual nevus, and a
malignant melanoma.

93
Q

What is Hutchinson sign?

A

Broad pigmented streaks of variegated color with cuticular pigmentation within the nail plate. It is associated with a
subungual melanoma.

94
Q

How is a subungual hematoma differentiated from a subungual melanoma?

A

Mark the nail plate and watch. If it is a hematoma, it will migrate distally. Ultimately, a nail bed biopsy is
recommended if even minor suspicion of melanoma exists.

Ebopras (32 decks)

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