What is bone made up of?
A protein matrix and materials. Such as calcium, phosphorus, copper, zinc and manganese.
How do bones go from growing to mature bones and where?
Endochondrial ossification and it is in the ephipseal cartilage regions.
What is the definition of endochonrial ossification?
Where cartilage cells are being transformed into bone cells.
What does it mean for bone growth to be predetermined?
Bone growth is predetermined but how well it is taken care of depends on it.
Why is it good for young foals to run around and play?
Because it stimulates the matrix, literally making more bone remodeling happen, which results in stronger, denser bones.
What happens if a horse is overly exercised?
There is too much pressure and too much effect on the bones, which will create negative bone remodeling.
What do both cells (osteoblasts/clasts) do together?
They work together to correctly mineralize the bone while it is growing.
Even though length growth in a bone might be done, what can still happen?
The density and strength of a bone can change.
What is the process of endochondrial ossification?
The body lays down layers of cartilage cells that helps the bone get longer and longer. They then convert to bone.
What three things affect bone remodeling?
Nutrition (how much mineral in vs. out), exercise (letting them play) and stress (too much exercise).
Why does bone remodeling occur?
Because the bone is constantly changing and changes to fit whatever circumstance the horse may be under.
What is the definition of correct bone remodeling?
It adjusts bone size and shape but horse remains sound.
What is the definition of incorrect bone remodeling?
Adjusts bone size and shape but results in blemish or unsoundness.
What is the most common break in the lower leg?
Torsion break of the cannon bone. "Twisting the cannon bone on a turn."
How do the joint capsules work and allow for movement?
Synovial membrane is along the inside of the joint capsule while it fills upw ith fluid to make the joints move easily.
What are the front leg bones from top to bottom?
Scalpula, shoulder joint, humerus, ulna, radius, elbow joint, knee, splint, cannon, sesamoids, long pastern, short pastern, coffin bone navicular bone.
What are the back leg bones from top to bottom?
Pelvis, hip joint, femur, stifle, fibula, tibia, hock, cannon, splint, sesamoids, long pastern, short pastern, coffin, navicular.
Describe tendons and what their function is.
Elastic and have the ability to stretch and deal with high tension. It has a tendon sheath containing synovial fluid which cushions the regions. Its function is movement.
What are the four main functions of tendons and ligaments?
Support (weight bearing), movement, protection (overextension, stress), absorb shock and concussion.
What are tendons and ligaments designed to do?
Hold the lower limb in correct position for locomotion in order to minimize injury and maximize energetics.
How do tendons act like a spring?
They store energy and release energy as they are stretched and relaxed.
What tendon and ligament take the brunt of the force during locomotion?
Superficial flexor tendon and suspensory ligament.
What is the purpose of the main and lateral tendons on the front of the cannon?
To bring the leg forward.
What is the purpose of the deep and superficial flexor tendons and where are they located?
Bring leg back. They are on the back of the front cannon.
Is it the front or the back where tendons stay seperate or connect?
Front = connect. Back = stay seperate.
What are the three check ligaments?
Radial check ligament, subcarpal check ligament, subtarsal ligament.
What are annular ligaments?
Bands of tissue that surround the circumference of a bone to hold a tendon in place.
What are capsular ligaments?
Surround a joint capsule and protect the joint capsule to provide extra support.
What are collateral ligaments?
Short bands of tissue that connect small bones of the lower leg. "Band-aids".
What ligaments keep your horse from essentially "rolling their ankles"?
Knee, hock, sesmoidean and navicular ligaments assist in preventing lateral movement!
What is the suspensory ligament?
Wide flat ligament that runs down the back of the cannon and divides multiple times to form a support mechanism "sling", for the fetlock.
What is the difference between a strain and sprain?
Strain is overstretching and weakening. Will inflame. While a sprain is fibers tearing and disconnecting.
How is shock absorption dispersed through the leg?
Starts at the bottom, hoof expands, frog compresses and digital cushions compresses, fetlock heads to the ground, knee compresses (due to all the little bones and fluid), heads up through the leg and dispersed through the muscle sling of the shoulder. Any leftover shock is dispersed through the back and up through the rider.
What is not good about suspensory injuries?
They take a long time to heal and will most likely never heal the same.
What is the fuction of the frog?
Shock absorption, traction, aids in circulation (moving the blood up to the heart).
What is the white line?
Junction of the hoof wall and sole. About 1/8" wide. It is the guideline for placing nails.
What is the sensitive structures in the hoof?
Soft tissue, which are blood vessels, nerve endings, etc., that supply nutrients and oxygen to insensitive structures.
What is the interlocking system?
It the system in which that is vital to the health of the hoof and helping support the coffin bone. It goes hoof wall, insensitve laminae, sensitive laminae, coffin bone.
Describe basic blood flow in the hoof.
Blood is forced through the hoof with pressure. Frog and the digital cushion comprss to help "push" blood back out of the hoof.
What are AV shunts?
They allow blood to bypass capillary paths if neccessary. It exists in animals so they can stand out in the snow for a long time and not get frostbit.
What happens if a horses sensitive structure in their hoof becomes damaged?
Damage to any of the sensitve structures can permantly affect the rate and quality of hoof growth.
What types of things add moisture to the hoof?
Standing water, bathing, certain hoof dressings. (Lanolin oil based is best. stick to light colours)
Why does Vitamin A play a big role in hoof nutrition?
Because it plays a big role in the horne tubule formation.
What way will one get the best result out of biotin for their horse and how long will you see a response?
In a three way combo with zinc, methionine combined with at least 15mg/day of biotin. 9-12 months.
Describe the long term study done on biotin.
Followed horses for 3 years on biotin supplementation. Found an improvement in hoof wall quality but no in the rate growth.
What are the four results of limb defects?
Creates unequal weight distribution, crooked movement, poor shock absorption and increased stress.
What does it mean for a horse to be toed out?
long/short pastern bone is crooked. They have the tendency to wing in.
What does it mean for a horse to be toed in?
Long/short pastern crooked in. They have the tendency to wing out.
What is bench knee?
Cannon bone doesnt come out of the center of the knee. It puts a lot of stress on the knee.
What does it mean for a horse to be base narrow?
Inward deviation of the knees. narrower at the base.
What is buck kneed/front at the knee?
Radius is set too far back. backbowed shape when viewed from side. dangerous for jumping.
Although in the front end, the legs should be straight to the ground, what is unique about the back end?
Not everything needs to be visually straight, everything needs to line up with the femur. Point of hock needs to turn out as much as the femur as well.
From the side, how do you tell if the back leg is the appropriate length and straight?
Point of buttock lined up with the back of the cannon bone.
What should the horne tubules look like with the appropiate hoof and pastern conformation?
What should the ideal way the underside of the hoof should look?
Quarters need to be symmetrical, concave sole, large frog.
Describe what broken back is.
Pressure is increased and creates strain on the deep flexor tendon which puts more pressure on the navicular bone and can lead to navicular disease. Often happens when the toe is left too long.
Describe what broken forward is.
More pressure on the front of the hoof. Creates a dished shape to the front of the hoof because it collapses. Associated with being club footed. = Can be genetic or an injury.
Describe what club footed is.
It could be genetic or acquired. can vary in severity. Acquired associated with contracted tendons or injury. If it is not genetic, you can fix it in 9mos-1yr.
Describe what underslung heels are.
Horne tubules are not parallel, very difficult to fix, it is considered a weakness, and the heels/bulbs appear to be touching the ground.
If your looking at a hoof from the bottom, how should the width look?
Width of foot 1inch back from the toe and 1/4 inch forward from the heel should be the same.
What are the three things that can contribute to contracted heels?
Lack of moisture, lack of movement and poor shoeing.
What does it mean for a horse to have a dropped sole?
Sole is below the hoof wall surface. Often happens due to founder. Very severe, most horses do not live. Very painful.
What should correct movement look like?
Breakover in center of toe, straight flight and flat landing.
With blemishes/unsoundnesses, what could this stress be from?
Conformation defects, overexertion, poor shoeing and movement.
What is the definition of a blemish?
A defect in form or function that does not interfere with the usefulness of the horse. Horse will be sound.
What is the definition of an unsoundness?
A defect in form or function that does interfere with the usefulness of the horse. Horse will be lame.
What is a capped elbow and what tissue is involved and why is it created? Blemish or unsoundness?
Also called a shoe boil. Subcutanious bursitis (swelling of the bursa on the point of the elbow). Irritation increases, synovial fluid is increased. Irritation from shoe when lying down or extreme irritation. Considered a BLEMISH. FLUID.
What is a popped knee, what tissue is involved and why is it created? Blemish or unsoundness?
Also called a capped knee. Inflammation on the front of the knee. Excess synovial fluid in joint capsules of knee or tendon sheath of lateral extensor tendon. FLUID. Can happen because of a horse being over at the knee, back at the knee, or jumping too young. BLEMISH OR UNSOUNDNESS, depends on severity!
What are bucked shins? What tissue is involved and why is it created? Blemish or unsoundness?
BONE. Also called shin splints. Caused by microfractures in the periosteum of the front of the cannon bone. Body lays down more bone to fix it. This stress comes frome exercise too young and twisting type activities. Unsoundness FIRST, then BLEMISH!
What are splints? What tissue is involved and why is it created? Blemish or unsoundness?
Additional bone between cannon and splint. BONE related. More common on the front than back end because of weight distribution. Can be a result of stress from conformation defects, limb interference, overexertion/twisting. Unsoundness FIRST, then BLEMISH!
What is a bowed tendon? What tissue is involved and why is it created? Blemish or unsoundness?
Usually occurs in flexor tendons (superficial). Caused by overflexion and fatique. Can happen suddenly or gradually. Involves sprain or strain. results in scar tissue which has less elasticity and circulation - horse will never perform the same. Horses can be SOUND but will always be a WEAKNESS!
What are osselets? What tissue is involved and why is it created? Blemish or unsoundness?
BONE. Hard swellings on front or side of pastern area. Due to overflexion of the fetlock (suspensory attachments irritate periosteum). OR can happen because of collateral ligament stress. BLEMISH! unless it lays down bone in joint area.
What are windpuffs? What tissue is involved and why is it created? Blemish or unsoundness?
Soft swelling in fetlock area. Excess synovial fluid production with stress. Caused by overextertion and poor pastern conformation. BLEMISH. FLUID related.
What are the two types of windpuffs?
Articular, which is joint related. Swelling of joint capsule. Swelling on sides.
Tendonous, which is tendon related. Swelling of the tendon sheath of the deep flexor tendon. Swelling occurs on the back!
What is ringbone? What tissue is involved and why is it created? Blemish or unsoundness?
BONE. Bone is deposited around the circumference of the pastern area. Can involve pastern joint (high) or coffin joint (low). Caused by excessive concussion. UNSOUNDNESS.
What is a sacroiliac luxation What tissue is involved and why does it happen? Blemish or unsoundness?
Hunter/Jumper bump - dislocation of the LS joint. Dislocation of the LS joint due to injury or twisting consistantly. BLEMISH.
What is a capped hock? What tissue is involved and why is it created? Blemish or unsoundness?
Irritation of bursa on point of hock. Causes an increase in synovial fluid production. BLEMISH. FLUID.
What is a thoroughpin? What tissue is involved and why does it happen? Blemish or unsoundness?
Soft swelling above point of hock. Involves swelling of the tendon sheath of the deep flexor tendon. Located on both sides. BLEMISH. FLUID.
What is a bogs spavin? What tissue is involved and why does it happen? Blemish or unsoundness?
Soft swelling on front and/or side of hock. Involves joint capsules of hock. Can happen due to excess exercise and poor conformation. BLEMISH or UNSOUNDNESS. FLUID.
What is a bone spavin? what tissue is involved and why does it happen? Blemish or unsoundness?
Additional bone which interfere with joints of the hock. Can happen because of poor conformation or excess stress. Can result inf usion of some of the bones or joint degeneration. BLEMISH = fusion. UNSOUNDNESS = joint deterioration. BONE related.
What are sole bruises/corns?
Bleeding in the sensitive sole. Same thing, just name is different because of location. Corns are bruises in the bars.
What are contributing factors to sole bruises/corns?
Trauma, excessive concussion, thin soles, rough terrain.
Why do abscesses happen?
Puncture wounds, trauma/bruises, white line disease and deep hoof wall cracks.
What is a White Line Disease?
Seperation of sole and hoof wall which allows infection inside. Actually a yeast infection.
What is sidebone?
Calcification of the lateral cartilage that supports the coffin bone. UNSOUNDNESS. Can be a sign of aging in old horses.
Why are founder and laminitis not interchangeable?
Because founder is a result of laminitis, and a horse cannot have founder without laminitis.
What are contributing factors to laminitis?
Overfeeding grain, excessive spring grass, sudden feed changes, poisonous plants, high fever, excessive concussion, retained placenta, obesity, Black Walnut shavings.
What is the classic theory of laminitis?
All result in endotoxemia. Toxins in the blood. Changes bodys blood flow priorities while dealing with toxins. Severity of episode is related to the amount of toxin.
What is the development of endotoxemia step by step with first stage of overfeeding grain?
Overfeeding grain, sugar is fermented in hindgut, produces lactic acid and decreases pH. Microbes die in large numbers and release toxins. Toxins absorbed into bloodstream. ENDOTOXEMIA.
What can happen when the death of the sensitive laminae happens?
Founder. Interlocking system is destroyed and coffin bone loses support and drops.
What are the coffin bone rotation numbers and percentages of horses that come back from it?
0-7 degrees: 90% return to normal.
7-15 degrees: 50% return to normal.
More than 15 degrees: 0%. Too severe.
Define the glucose/insulin theory.
Hoof lamellar tissue is highly dependent on glucose, the lack of glucose as a nutrient results in tissue death. High levels of insulin have been shown to trigger laminitis.
What is fructan?
Non-structural carbohydrate. It escapes foregut digestion. Used experimentally to induce laminitis. But is also in grass!
What is the enzymatic theory?
Laminitis is an autodegradation of the lamellar connective tissue occuring when enzymatic remodeling escapes control.
What type of treatment slows down the enzymatic theory?
Cold treatment (cryotherapy) slows down enzymatic theory. It isnt vascular becuse of the AV shunts. Enzymes are involved.
Once your horse has laminitis, how do you deal with it?
Minimize toxin absorption (mineral oil with stomach pump), bute, banamine, realign the coffin bone with shoeing.
What are the four high risk factors for laminitis?
Previous bout of laminitis, "easy keepers", high grain diet, lush pasture.
What are symptoms of laminitis?
colic, sweating, increased vitals, hot feet, hard pastern pulse, sawhorse stance.
What shoeing techniques are done to horses that are dealing with the aftermath of laminitis?
Heart bar often with full pads/cushions. It supports the coffin bone from underneathe and reduces tension on laminar connections.
What is a wooden shoe/steward clog?
Cover entire bottom of hoof with wood for support. More cushion. use screws not nails.
What are risk factors to navicular disease?
Genetics (QH, STBD, TB), small feet, broken backed, underslung heels, steep pasterns, obesity, concussion, sporatic conditioning.
Why could naviular bursitis be involved in navicular disease?
Inflammation of the bursa blocks blood flow and interferes with bone remodeling.
What are the negative correlation with navicular disease?
The angle of the coffin bone and the ground. The heel height and toe height ratio.
What are signs of navicular disease?
Decline in performance, choppier gait, unwillingness to jump, irregular lameness, shortness of stride.
What is nerving?
A way to manage navicular pain. They actually make it so the horse cannot feel the pain but they will always have the disease.
What shoeing considerations should you take with a horse that has navicular disease?
Egg bars with wedge pads. RUN if you see this!
What is a developmental orthopedic disease?
A DOD encompasses all general growth disturbances in the growing stage.
What are the four different DOD's that we learned in class?
Osteochondrosis, Angular limb deformaties, flexural deformities, ephysisitis.
What is angular limb deformities?
Excessive deviations as looked at from the front or back that are excessive from side to side. Bone related.
What are flexural deformities?
Problems with normal flexion of a joint viewed from the side. Joint is either in an abnormal position or does not have the normal range of motion. Soft tissue related.
When a horse has contracted tendons, how can you potentially treat it?
Giving them oxytosin - causes relaxation. Or cutting the check ligaments because the hoof is in a bad position and being pulled up.
What is osteochondrosis?
Cartilage cells dont convert to bone, get bigger, which creates no support, they then die, body takes it away, which creates holes (cysts) that are left in the bone, they work themselves to the surface over a lifetime. They develop in the early stages, but you will not see it until your horse ages.
What are contributing factors osteochondrosis?
Sporatic exercise, excessive growth (providing too many calories), genetics, mineral imbalances (copper), fluctuations in insulin/glucose, mainly with growth.
If your horse is still a baby, and youre worried about OCD, how can you prevent it?
reduce concussion and check diet!
If your horse is an adult, how can you treat OCD?
They will remove the parts that are floating around and most likely recieve joint injections.
How is obesity a problem?
It can lead to many problems such as laminitis and possibly founder. As well as the overfeeding aspect can lead to Osteochondrosis later on in a horses life.
Mineral imbalances also can create OCD. Which ones?
Calcium, phosphorus, copper. Found in higher incidence in copper deficient mares' foals. They had a high chance of OCD. So this means it happens in utero!
Where are the most common places to see an OCD lesion/cyst?
Shoulder joint, elbow joint but primarily the fetlock joint, stifle joint.