The Equine Hoof (7) Flashcards

1
Q

What is the periople?

A

protective layer to prevent desiccation
analogous to a cuticle

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2
Q

What is the wall of the hoof? What is its function?

A

primary weight-bearing structure
keratinized, tubular epidermis
protection, force dissipation, traction

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3
Q

What are bars of the hoof? Its function?

A

extension of the wall
provides additional weight-bearing surface
prevents excessive expansion —> buttress

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4
Q

What is the heel of a hoof? It’s function?

A

entire palmar/plantar aspect
for shock absorption —> distributes forces

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5
Q

What is the white line? It is the area where _______

A

junction between solar and laminar epidermis, sole and hoof walls meet
area where nails are driven in on a shod horse

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6
Q

What is the sole? Its function?

A

protects bottom of P3
bears less weight compared to wall (bottom of hoof is concave)
provides traction

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7
Q

What is the frog? Its function? What is contained in the frog?

A

lies over the digital cushion —> peripheral pump
provides traction
central sulcus & collateral sulci

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8
Q

What is the coronary band?

A

hoof wall (coronary epidermis)
overlying coronary dermis

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9
Q

What is the coronet?

A

junction between hoof wall (coronary epidermis)
& skin (epidermis)

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10
Q

The hoof epidermis is _______

A

keratinized

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11
Q

What are the dermal layers of the hoof?

A

coronary dermi
laminar dermis

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12
Q

What are the epidermal layers?

A

coronary groove
coronary epidermis (stratum medium)
laminar epidermis (stratum internum)

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13
Q

Hoof growth has about _____ per month

A

6-9 mm

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14
Q

How does the hoof grow? (3 steps)

A
  1. keratinized coronary epidermis formed by basal epidermal cells at coronary band tubular
  2. continuous with keratinized laminar epidermis
  3. desmosomes detach between epidermal and dermal lamina to let coronary and laminar epidermis “ratchet” or move down
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15
Q

Regarding sole growth, horn tubules are oriented [horizontally/vertically]

A

vertically

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16
Q

Sole growth is limited by ______

A

curling of tubules at ground
- slower than wall growth

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17
Q

T/F: The horse walks on its third phalanx

A

FALSE - P3 is suspended in hoof capsule by the lamina

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18
Q

The laminar dermis ______ & supplies the laminar epidermis

A

interdigitates

19
Q

What happens if the suspensory apparatus fails?

A

laminitis - sometimes
P3 rotation
deep digital flexor pulls P3
sinking - P3 should not be anywhere near bottom of foot

20
Q

Why does the suspensory apparatus of P3 fail?

A

insulin dysregulation
endothelial cell and vascular dysfunction
metabolic syndrome & insulin resistance
pars pituitary intermedia dysfunction
endotoxemis - colic, retained placenta, colitis
physical demand

21
Q

What are the blood & nerve supply to the hoof?

A

median/lateral palmar/plantar digital

22
Q

Where do vessels enter on the hoof?

A

palmar/plantar aspect of P3
arteries through foramen in P3
venous drainage primarily along dorsal border of P3
venous plexus

23
Q

What is this?

A

palmar/plantar digit artery & vein

24
Q

What comprises the venous plexus?

A

palmar venous plexus
dorsal venous plexus
coronary venous plexus

25
Q

Where does the venous plexus drain into?

A

digital veins

26
Q

Where is the palmar venous plexus?

A

in sole corium, around toe between sole and digital cushion

27
Q

Where is the dorsal venous plexus?

A

in laminar corium

28
Q

Where is the coronary venous plexus?

A

at coronet - in coronary and perioplic corium

29
Q

What vessel is this?

A

palmar digital a/v

30
Q

What are collateral cartilages? Function?

A

attach to P3
structural support for heel bulbs
shock absorption - dissipates force through their expansion
involved in blood pumping action of foot

31
Q

Label 1-6

A
  1. P1
  2. P2
  3. P3
  4. navicular bone
  5. digital cushion
  6. frog
32
Q

T/F: There is no muscle in the digit and therefore less effective venous drainage

A

TRUE

33
Q

How does the hoof act as a pump? Which structure?

A

digital cushion functions as a pump
horse bears weight: digital cushion expands and veins compressed —> diastolic phase
horse lifts hoof: digital cushion contracts and veins open

34
Q

When the horse bears weight, the digital cushion [expands/contracts] and veins are [open/compressed]. Blood [pools in/forced out of] venous plexus, and it is the [systolic/diastolic] phase

A

expands
compressed
pools in
diastolic

35
Q

When the horse lifts the hoof, the digital cushion [expands/contracts] and veins are [open/compressed]. Blood [pools in/forced out of] venous plexus, and it is the [systolic/diastolic] phase

A

contracts
open
forced out of
systolic

36
Q

How does the navicular bone (distal sesamoidean bone) acts as a pulley?

A

lowers strain on DDFT as it changes direction to cross coffin joint
lowers work of DDFT to act on P3 (increase mechanical effort)

37
Q

Label 1-3

A
  1. collateral sesamoidean (suspensory) ligament of the navicular bone
  2. navicular bone
  3. impar ligament
38
Q

Label 1-4

A
  1. deep digital flexor tendon
  2. impar ligament
  3. collateral sesamoidean (suspensory) ligament of the navicular bone
  4. navicular bursa (protects ddf tendon)
39
Q

Label 1-2

A
  1. collateral sesamoidean (suspensory) ligament of the navicular bone
  2. impar ligament
40
Q

Label 1-2

A
  1. proximal border
  2. distal border
41
Q

Label 1-3

A
  1. synovial fossa (superimposed on distal border)
  2. collateral sesamoidean (suspensory) ligament of navicular bone
  3. impar ligament
42
Q

Label 1-4

A
  1. coffin bone
  2. short pastern
  3. navicular bone
  4. deep digital flexor tendon
43
Q

What is function of the hoof?

A

traction
shock absorption
support of skeletal column
protection of inner structures
venous return (peripheral pump)

44
Q

What are synovial structures of the hoof?

A

DIP joint
flexor tendon sheath
navicular bursa
deep digital flexor tendon