Anatomy and Phys Flashcards
What is the outside of the hoof wall made out of?
Keratin
What are the three general layers of the hoof wall?
Stratum externum
Stratum medium
Stratum internum
What are the more specific layers of the walls if you break the general layers further?
Stratum externum
Pigmented stratum medium
Non pigmented stratum medium
Epidermal laminae
Dermal laminae
Dermis
(T/F) Only the epidermal laminae is the only one that has primary and secondary layers.
False - dermal laminae also contains primary and secondary layers.
What is the epidermal laminae made out of? What about the dermal laminae?
Epidermal - keratin
Dermal - collagen
Where are the basement membranes and basal cells located?
In the secondary layer of the dermal laminae
Which location does the blood end up on to nourish the hoof wall?
Primary dermal laminae
Where are the matrix metalloproteinases located?
Lamellar basal cells
What two enzymes allow the growing hoof wall to move past the stationary distal phalanx?
MMP (Matrix metalloproteinases) and TIMP
Lamellar epidermal cells and adjacent basement membranes are constantly responding to the stress and strains of growth and locomotion by releasing ____ to accomplish whatever cellular reorganization is required.
MMP (Matrix metalloproteinases) and TIMP
What are the two requirements to maintain the bond in the lamellar interface?
Oxygen and glucose
How much does the hoof wall grow in a month?
6-10mm in a month
What are the approximate times of regeneration of the hoof wall (depending on the location of the growth)?
Toe - 12 months
Quarter - 6-8 months
Heel - 4-5 months
What are the factors affecting hoof wall growth?
Genetics, Nutrition, Season (time of year), Conformation, Pathologies, Exercise
What are the two general aspects of hoof shape?
Wider at the ground than the coronet
Sole slightly concave
If a horse foot is more round than bow shaped (at the bottom) is it a hind foot or a front foot?
Front foot
(T/F) The toe is thinner while the heel is thicker so loading can happen and prevent hoof capsule fractures.
False - toe is thicker while heel is thinner
What does it mean that you want to achieve a matched hoof pastern axis?
The dorsal wall of the hoof will match the angle of the bony column of the foot → allows spreading of the load evenly between all structures of the foot
What should the length and angle of the heel be in relation to the dorsal hoof wall in an appropriately trimmed horse hoof?
Angle should match the dorsal hoof wall and the heel would optimally be about ⅓ the length of the dorsal hoof wall
The frog would optimally extend over what percentage of the length of the hoof?
60%
(T/F) A positive palmar angle is optimal, average is usually 3-5 degrees.
T, do not want a flat/negative palmar angle
What is a broken back hoof pastern axis?
When the angle of P2 and P1 are steeper than P3
What structures are overloaded with a broken back HPA and what conditions can that predispose the horse to?
Overloaded → DDFT, navicular bone, P2, and P1; conditions → navicular dz, ring bone, coffin joint inflammation, hoof cracks, and sheared heels
What is the main positive function of a hoof pad?
Recruits the sole and frog in load sharing, others → protect and support, align the hoof pastern axis, protect wounds, act as artificial sole depth, aid with shock dissipation
What substance can be added to packing material for a hoof pad that is a good antimicrobial?
Copper sulfate
Why must silicone be used under a hoof pad?
Bc it does not bond to the sole
Why is oakum a good option for horses with white line disease and/or abscesses?
It allows for drainage → is non-sealing
What are some shoe options that can ease breakover?
Rolled toe, rocker toe, square/blunt toe, and bar shoes
What are the 4 general biomechanical concepts in farriery?
Ground reaction force
Center of pressure
Distribution of force
Moments about DIPJ
What is the equation for ground reaction force?
Weight = Mass * 9.8m/s/s
What is the term that describes the force exerted by the ground on the body?
Ground reaction force
What is the term for point through which the ground reaction force acts on the foot?
Center of pressure
Can the center of pressure be moved? If so, how?
Well yeah - moved by farrier maneuvers aka trimming and shoeing
If the lever is vertical to the axis how much movement will it have?
0
(T/F) The base of support does not correlate with the moments about DIPJ.
True
If we place a heel elevation, what will that do to the DDFT?
It shortens the tendon which will in turn decrease the tension in the tendon
In general, which structures are stressed under tension? (3 are listed)
Laminae, tendon, ligaments
In general, which structures are stressed under compression? (3 are listed)
Tissues of the sole, bones, joints
What are the 3 aims in farriery related to biomechanism of the foot?
Change the distribution force
Move center of pressure
Decrease moments of the DIPJ (static and dynamic)
What is breakover?
Last remaining point of the toe before it leaves the ground
Where is the adequate place for breakover to be?
By the most distal part of P3
If we place a toe wedge on a foot, what structures are going to have increase stressed? How about decreased stressed?
Increased: DDFT/Navicular region/ICL/ALDDFT
Decreased: SL/SDFT
What are the 4 reasons they want to put on a shoe on a horse?
Protection, Alter gait, Traction, Treatment
What are some consequences of horse shoes?
Increases shock/concussion to the distal limb, traumatic hoof wall loss, puncture wounds from clips/nails, spring/twisted shoe, injury when kicking, nail too close to sensitive structures
What is the main difference in a hoof trim if you are going to put a shoe on or not?
Shoe → trim shorter, should be flat with a sharp edge, no shoe → outer edge should be rounded to prevent chipping and should be left longer to allow for wearing
What are the two most traditional material for horse shoes?
Aluminum and steel
Which of the two (aluminum or steel) weighs more?
Steel
Why do some farriers do not like aluminum for shoes?
Hard to deal with
More expensive
Less durable
What are the materials less commonly used for horse shoes?
Titanium, plastic, rubber, urethane, wood
What are the three traditional horse shoe types?
Plain stamped, 3/4 fuller, fully fullered
Which of the traditional horse shoe types has the most traction? The least?
More traction - fully fullered
Less traction - plain stamped
How much bigger should the web be than the hoof wall?
2x bigger
What should the shoe thickness depend on?
Size and discipline
What structure does the heart bar shoe load?
The frog mostly (part of the heel as well)
What are fish tail shoes mostly used for?
Foal flexural limb deformities (broken back)
What are patton bar shoes mostly used for?
Flexural limb deformities
What is the glue on shoe that is indirectly glued to the hoof wall?
Soundhorse technologies series 1
Soundhorse technologies series 3
Where can clips be located?
Toe, quarter, side
Which modification on a shoe do you have to shave part of the toe during trimming and helps with breakover?
Rocker toe shoe
Which shoe would you place if a horse hits their own legs and you want to correct it? What is the downside?
Trailer shoe - should not be worn if they are out with other horses (it is a hazard)
Which shoe would you like to place if in the winter the places where the horse lives there is a lot of snow?
Drive in studs
What shoe will have studs that goes into the mud?
Caulks
What are some positive functions of pads?
Protect and support
Recruit the sole and frog in load sharing
Increase overall foot length
Align the hoof pastern axis
Protect wounds (abscesses, clip punctures, nail punctures)
Act as artificial sole depth
Aid with shock dissipation
What are some negative functions of pads?
Pressure and pain
Pads can apply pressure on compromised areas resulting in discomfort
Example: dense/firm packing materials used for a horse with minima sole depth
Example: packing materials applying pressure over the navicular region
Increase overall foot length
Can reduce traction
Trap dirt/debris
Can create anaerobic bacteria growth
What are the materials we can we use for pads?
Leather, plastic, urethane, closed cell foams pads
Which pad material will extend and contract?
Leather
What pad material will not deform or crush and is not gas permeable?
Plastic
What type of pads are there?
Full, rim, bar, wedge, frog, snow
What are the different materials (“types”) of packing materials?
Urethane, silicone (window/bath caulking), silicone impression materials, oakum
Which packing material should be used under pads since they do not bond to sole?
Equi-pak soft
Silicone (window/bath caulking)
Sil-pak
Silicone impression materials
What are the 3 types of adhesives?
SuperFast, BoviBond, Adhere
What can we use as an addition to silicone (window/bath caulking) to decrease set time (to 5-10 min) and antimicrobial?
Copper sulfate - antimicrobial
Betadine - decrease set time
What is the set time for silicone impression material?
3-5 minutes at 75 degree weather
What is the most common size of a nails on horses?
5 is the most common size
Copper sulfate most effective against what type of bacteria?
Anaerobic microbes
Where does the center of weight distribute to in a broken back hoof pastern axis?
Palmarly
What are the two treatments for broken back hoof pastern axis?
Trim/shoe to establish hoof pastern axis
If trimming alone doesn’t fix it then you can use a heel wedge
What term do we use when the hoof angle is steeper than the pastern angle?
Broken forward hoof pastern axis
What structures will a broken forward hoof pastern axis stress?
Suspensory ligament, superficial digital flexor tendon, coffin joint, wall/hoof itself
What are the treatments for a broken forward hoof pastern axis?
Treat the primary cause
Trim to establish a proper hoof pastern (lower the heel)
To take off a shoe what is the first thing you have to do after cleaning the sole?
Cut the remaining clenches of the nail with a clinch cutter and a hammer
What tool can you use to pull of a nail individually?
Crease nail puller
If the last 2 nails aren’t budging when you use a crease nail puller, what tool can you use that will take the shoe off?
Shoe pullers
How can you differentiate a shoe puller from nippers?
Nippers have the wings at the bottom (the tool flares out) and they are sharper than the shoe puller
What are some factors to consider when choosing a shoe?
Durability, weight, cost, ability to shape and modify, horse’s activity and environment
What are some pros for machine made shoes?
Saves time
Wide variety of sizes and styles
Requires less skill/training
Requires fewer tools
What are some cons for machine made shoes?
Require modification
Nail holes are typically not pitched appropriately
Clips are typically even thickness
Can be costly to carry large inventory of shoes for every situation
Therapeutic shoes are typically very expensive
What are some pros for hand made shoes?
Customization
Ability to carry smaller inventory
Nail holes are in the correct location with correct pitch*
Clips are a tapering thickness and in a chosen location
What are some cons for hand made shoes?
Requires more skill
Requires more tools
Time? (Loss of time initially, saving of time with increase in proficiency)
What tools are used to trim a hoof?
Wire brush and hoof pick (to clean), hoof knife, nippers, rasp, Hoof Buffer and Sanding Sponge
What things do you want to think about when choosing a shoe type?
Web width, thickness, fuller or plain stamped, flat or concave stock, open heeled shoe vs bar
What are the two types of attachments?
Nail or glue
What are the two types of glue on shoes?
Indirect and direct
When do we use glue on shoes?
Used typically only when nailing cannot be safe and secure
Where do you place the nails on the shoes? Is that the same place they get white line disease?
Place nails - white line
White line disease - NONPIGMENTED PART OF THE STRATUM MEDIUM - so no
Where do we place the first nail on the shoe?
The most upright nail underneath your dominant hand
What tools do you use to place a shoe?
Hammer, clincher, gauge, clinch block, rasp, nail nippers, nails
What does the hoof care and decisions made early in life in a foal impact? (3 answers)
Conformation, soundness, athletic performance
(T/F) Hoof care evaluations and decisions should be performed by a vet farrier team.
True
When should the first trim occur for a foal?
At the 30 day mark (unless disease pathologies/confomational defects require trimming shoes)
What are the principles of corrective farriery for a foal?
Correct/rebalance feet as often as needed
Acrylic extensions or shoes should be used only when indicated
Beware of creating secondary deformities*
(T/F) Foal feet are not completely formed.
True
What do foal feet have instead of the sole’s horn?
Eponychium
How is the foal foot not the same as an adult when it comes to symmetry?
The bottom is more narrow than the coronet this will change at the 4-6 mark
When will the line of the coronet disappear?
4 month mark
How many hoof cycles will the foal complete in the first year?
2
What two structures should be maintained during trimming of a foal?
Sole and frog
(T/F) The toe should be more round/square to prevent avulsion in foals because they are born with a pointy toe.
True
What is the term we use when the foal has her heel on the ground because of a tendon?
Hyperextension/Flexor laxity
Flexural laxity is common in which types of foals?
Premature and dysmature
What type of shoe would you use in a case of flexural laxity?
Heel extension - craft wood is better and you can attach it with urethane adhesives because they are quick to set up (or you can use ibex cuffs)
What should be the first thing you do when you are preparing a foot for an adhesive?
DRY IT OUT and clean (hoof wall and sole)
What are the steps to think about treatment when looking at a foal with bad confirmation?
- Trimming
- Extension/Shoe
- External fixators
What is the biggest thing when trying to deal with a contracture deformity on a foal?
There might be an underlying issue
(pain, contracture physitis, OCD, P3 fractures)
What is the treatment with a contracture deformity?
Treat underlying condition
Heel extensions
(T/F) Moderate to severe cases with contracture deformities will respond to trimming and shoeing only.
False - surgery is often indicated (tenotomy)
For hoof extensions, would you use lateral or medial extensions to correct varus deformities?
Lateral extension for varus, medial for valgus
Do you want a toe or heel extension for DIP flexural deformities?
Toe extensions, and should trim the heel
Why does angular limb deformities happen in foals?
Incomplete ossification of the carpal and tarsal bones
What structures will have laxity in an angular limb deformity?
Ligaments, tendons, and muscles
(T/F) Angular limb deformities will only have asymmetric growth of the epiphysis.
False - also have asymmetric growth of the metaphysis of long bones
Will shoes/extensions only help with angular limb deformities?
Will not help alone and we should radiograph those
Of the sites where angular limb deformities occur (fetlock, tarsus, carpus), rank them from most to least common.
Most common → carpus, fetlock, least common → tarsus
What are perinatal factors that can lead to congenital angular limb deformities?
Intrauterine malpositioning, overnutrition of the mare, cuboidal bone hypoplasia, and incomplete development of MT/MC II and IV
What is the treatment of asymmetric growth of metaphysis/epiphysis based on?
Modifying chondral growth
What are the differences between pathologic and physiologic compression forces?
Pathologic if you add more compression to the side of angulation you might make it worse while physiologic compression you can fix it.
How can chondral growth patterns be modified? (3 things)
Controlling activity
Trimming and shoeing*
Surgery
What does the method of treatment depend on in modifying chondral growth?
Degree of deformity
Physeal growth rate of affected part
Total amount of growth remaining in the affected part
In which part do you have more time to fix conformational issues? (Fetlock or carpus)
Have more time with carpus to make corrections than fetlock (3 month timeline)
How often should you correct trim and shoe a foal with angular deformities?
Every 2 weeks
(T/F) Shoe extensions should always go to the opposite side of the deviation.
True - and trim on the side of the deviation (where hoof wall extends more)
What is described as white line disease?
Progressive hoof wall separation
Can the white line disease go all the way the coronet or does it stop at a certain point?
Go all the way up
(T/F) The white line disease will invade the dermis which is why its so hard to treat.
False - it will not invade the dermis (will stay superficial to the lamellae interface)
What is the first thing that needs to happen for white line disease to start?
An initial separation that will lead to opportunistic microbes to invade
What are the risk factors of white line disease?
Mechanical factors
Environmental factors
Microbial factors
Genetic factors
Conformational factor
Why would you want to take radiographs in a white line disease case?
To delineate and show the extent of the white line because you need to debride to healthy appearing margins
(T/F) Horses with white line disease will be lame.
False
What are some conformational factors that will lead to white line disease?
Chronic Laminitis
Flexural Limb Deformities
Flares/Distortion of the Hoof Capsule
Crena
What steps do you need to take to treat white line disease?
Reduce/limit predisposing factors
Debride to a healthy appearing margin
Treat topically
Maintain in a clean and dry environment
Apply shoes +/- frog and sole support as needed
What tools should you use to debride white line disease?
Half round nippers (they bite into dorsal hoof wall)
Large/Small loop knife
Bone curettes
Carbide burr
What solution can you use to make sure there is owner compliance in the treatment of white line disease?
Tincture iodine
If you add a shoe and a pad on a white line disease foot for long term bandaging, when should it be replaced?
6-8 weeks
What is a keratoma?
A tumor of the keratin producing cells of the hoof wall
What would a radiograph of a keratoma show?
Smooth margined defect in the third phalanx secondary to pressure necrosis from a mass
What would be your first sign to look for a keratoma since they are usually not apparent in a horse?
Full thickness crack that you cannot repair
How will you treat a keratoma?
Tumor must be removed in its entirety or it will regrow
What is a prognosis of a resection of a keratoma?
Good prognosis with complete resection
What is the main goal of medically managing a keratoma?
Eliminate the risk of a subsolar abscess
How would you stabilize the hoof wall after a keratoma resection?
Metal plates for 4-6 months to keep it stable and load the healthy structures (sole and frog)
What do hoof cracks usually associated with?
Hoof imbalances associated with confomational faults
What would be your treatment for a hoof crack?
Correction of imbalance (as best as possible)
Debridement of the crack
Stabilization of the crack
Support of the digit
Commitment to follow up
What three main forces act on the hoof wall?
Tension, compression, bending
How long can it take for a hoof crack to replace?
4-12 months depending on location
What is the most common treatment of hoof cracks in VMCVM?
Plating the fracture with fiber fabric and PMMA
Where will the hoof crack more readily in a varus conformation?
On the lateral side (more upright) - opposite for valgus
What are the layers you want to debride with a hoof crack?
Stratum medium and stradum externum
In what direction will the forces of coronet and the bottom of the foot going in a full thickness toe crack?
Coronet are going towards the crack while at the bottom it is going away from the crack
What type of shoeing and trimming are you going to do for a toe crack?
Load the digit (frog and sole) and toe modifications to ease breakover
In a toe crack, what is the main problem with the imbalance of the foot?
The center of pressure is not where it is supposed to be - it is more palmar
What materials are the most common in a glue on shoe?
Urethane, aluminum and wood
What is one material that will not need adhesives to glue on?
Steel
What are the two urethane materials for adhesions?
Adhere and Superfast
How long does it take for urethane material to set up? (Adhere/SuperFast)
30 sec - 1 min
How long does it take for Bovabond to set up?
30 seconds
What are some indications to glue on a shoe?
Inability to safely and securely attach shoes with nails
Reduce/prevent shoe loss
Horses that have been sedated
Horses that have been “blocked/nerved”
Horses under general anesthesia
What are some potential problems with glue on shoes?
Cost
Not a helpful horse
Not ideal environment to place a glue on shoe
Can make a disease worse (white line disease)
(T/F) To place a glue on shoe the previous nail holes of shoes should be debrided away.
True
(T/F) You can touch the hoof wall after cleaning it before placing a glue on shoe
Fuck no
What is the only downside to indirect glue with PMMA?
Have to hold up the foot the entire time- takes awhile to solidify
(T/F) You can leave the glue on shoe for rads
False - glue will look like artifact
(T/F) You gotta be nice to the farriers
True cause we love travis and hopefully he is nice with his questions
