Lecture 7: Musculoskeletal - Equine hoof (Exam 1) Flashcards
No hoof = ?
No horse
Define the periople
Protective layer to prevent desiccation analogous to a cuticle
Label the orange circle
Periople
Define the wall of the hoof
Primary weight bearing structure protection, force dissipation, traction, keratinized, & tubular epidermis
What are the three parts of the wall
- Toe
- Quarter
- Heel
Label the following
Define the Bars
- Extension of the wall
- Provides additional weight bearing surface
- Prevents excessive expansion (buttress)
- Strengthens the palmar aspect
Label the teal & pink line
- Teal: Bar
- Pink: Wall
What does the heel do
- Shock absorption
- Distributes of forces
Describe the while line
- Junction btw/ the solar & laminar epidermis
- Area where nails are driven in on a shod horse
What is this
The white line
Label the following:
Describe the sole
- Protects the bottom of P3
- Bears less weight compared to the wall (bottom of the hoof is concave)
- Provides traction
Label the purple area & the black arrow:
- Purple: Sole
- Black arrow: Angle of the sole
Define the frog
- Lies over the digital cushion (peripheral pump)
- Provides traction
Label the blue triangle, yellow lines, & orange line
- Blue = Frog
- Yellow = Collateral sulci
- Orange = Central sulcus
Why is it called the frog
Probably reminded the early railroad men of the triangular area where 2 tracks met
Define the coronary band
Hoof wall (coronary epidermis) Overlying the coronary dermis
Label the yellow line
Coronary band
Describe the coronet
Junction btw/ the hoof wall & the skin (epidermis)
Label the blue line
Coronet
Label the following:
Corium = ?
Dermis
Hoof epidermis is (Keratinized/unkeratinized)
Keratinized
List the dermal layers
- Coronary Dermis
- Laminar Dermis
Label the following:
Describe the coronary dermis
- Supplies keratinized coronary epidermis that forms the tubule & intertubule horn
What does the laminar dermis supply
The laminar epidermis
Label the epidermal layers
What is the mm of hoof growth per month
- 6 to 9 mm
- may be ~ 3 mm in winter
Label the following
Explain the steps of hoof wall growth
- Keratinized coronary epidermis formed by basal epidermal cells @ the coronary band (tubular) (purple line)
- Continuous w/ keratinized laminar epidermis (orange line)
- Desmosomes detach btw/ epidermal & dermal lamina to let coronary laminar epidermis “ratchet” (move down) (blue arrow)
Label the following:
Describe sole growth
- Horn tubules orientated vertically
- Growth limited by curling of tubules @ ground
- Slower than wall growth
T/F: Horses walk on the third phalanx
F; P3 is suspended in the hoof capsule by the lamina
Laminar dermis -blank- & supplies the laminar -blank-
- interdigitates
- Epidermis
Label the following:
What happens if the suspensory apparatus fails
- Rotating
- Sinking
Why does the suspensory apparatus of P3 fail
- Under investigation
- Insuling dysreg
- Endothelial cell & vascular dysfun
What conditions can cause the suspensory appartus of P3 to fail
- Metabolic syndrom & insulin resistance
- Pars Pituitary Intermedia Dysfunction (PPID or Cushing’s)
- Endotoxemia (like colic, retained placenta, colitis)
- Physical demand
How do arteries enter the palmar & plantar aspect of P3
Through a foramen
Where does venous drainage primarily occur on the palmar & plantar aspect of P3
Along the dorsal border of P3
Name the extensive branching of veins found in the hoof
Venous Plexuses
Label the following:
Describe the palmar venous plexus
- In the sole corium
- Around the toe
- Btw/ the sole & digital cushion
Where is the dorsal venous plexus
The laminar corium
Describe the coronary venous plexus
- At the coronet - in the coronary & perioplic corium
- Drains into the digital veins
- Cuts @ the coronet bleed
Label the following:
Digital vein?
Describe the collateral cartilages
- Attaches to P3
- Structural support for heel bulbs
- Shock absorption (dissipates force through their expansion)
- Involved in blood pumping action of the foot
Label the following:
Label the following:
What functions as a “pump” in the hoof (or digit 3)
Digital cushion b/c there is no muscle in the digit
Explain how the digital cushion functions as a pump
- When the horse bears weight the digital cushion expands & the veins are compressed which causes blood to pool in the venous plexus & digital cushion (diastolic phase)
- When the horse lifts the hoof the digital cushion contracts & the veins open so that blood is forced out (systolic phase)
Describe the navicular bone (Distal sesamoidean bone)
- Functions as any other sesamoidean bone
- Acts as a pulley to decreas strain on the DDF tendon as it changes direction to cross the coffin joint & decreases the work of the DDF tendon to act on the P3 (increases the mechanical effect)
Label the red line
The navicular bone
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What parts/how of the hoof are needed for traction
- Frog
- Concave shape of the hoof
- Wall
How does the hoof help with support of the skeletal column
- Weight of the horse being transmitted via the lamina to the hoof wall
- Suspends P3
What parts/how of the hoof is needed for shock absorption
- Digital cushion
- The ability to expand the hoof @ the heels
Whats parts/ how does the hoof protect the inner structures
- Periople protects them from evaporation
- Hoof wall protects the lamina
What parts/how does the hoof use for venous return (peripheral pump)
- Frog
- Digital cushion
- Collateral cartilages
Label the following:
