EQUINE THEORY

Problems caused in the horse by subluxations (skeletal dislocations) in the following systems:

Biomechanics

To understand the normal biomechanics of the running horse, think of the front legs as the fulcrum of the seesaw. The head and neck comprise one side of the seesaw, the back and rear end form the other half.

When a horse breaks from the gate, they raise their head and neck, causing their rear end to lower, allowing the horse to then leap forward using their rear legs. When the horse lands on their front legs, they lower their head and neck, which raises their rear end, allowing the horse to reach forward with their rear legs. When the horse plants their rear legs, they then raise their head and neck, lowering their rear end, to leap forward again, repeating the cycle.

The horse with a subluxated sacrum carries their head and neck higher than normal, to relieve the pain occuring in their sacral region. They do not have a biomechanical problem leaping forward from the gate. The problem occurs when they land on their front legs, and begin to lower their head and neck. Due to pain in their sacral area, they do not lower their head and neck low enough for their rear end to rise as it should. Reaching forward with their rear hooves, they hit the ground too soon. They cannot collect properly, nor round their back. This shortens their stride behind. Due to the shortened positioning of the rear legs, the horse is unable to leap as high as normal. The front legs, instead of being fully extended when they hit the ground are not fully extended, asuding the stride to be short, and a hard choppy gait. This adds to the concussion to their front legs, leading to front leg and hoof problems (navicular disease).

Due to the sacral dislocation, the horse is unable to shift leads behind. Most of them do a little hop to bend the spine laterally to bring forward the hip that is stuck to the rear. This curve in the spine causes the horse to shift their front legs to one side, causing most of the weight to be thrown into one front leg. This causes hyper extension of the ankle and fetlock causing:

  1. Chips
  2. Fractured sesamoids
  3. Fractures of the cannon bone
  4. Bucked shins ("Green stick" fractures of the cannon bone. In older horses this shows up as a slab fracture out of the front of the cannon bone.)
  5. Bows
  6. Strained or sprained check ligaments
  7. Arthritic changes (Osselets, Ring bone & Side bone) - see <Treatment for Osteoarthritis>

This also causes compression of the knee, causing:

  1. Chips
  2. Micro fractures of the third carpel
  3. Slab fractures of the third carpel
  4. Arthritic changes

Skin

The continual secretion of adrenalin, greatly reduces the neural impulse, and blood supply to the skin. The oil glands, sweat glands and hair follicles stop functioning normally. The hair coat becomes drab, the skin becomes dry, the horse may stop sweating. Some horses do not shed or shed poorly This makes the horse more prone to skin diseases, parasites and heat exhaustion.

Mucous Membranes

The continual secretion of adrenalin, greatly reduces the neural impulse, and blood supply to the mucous membranes. The membranes become less moist. Immunoglobulin A (IgA) has difficulty crossing the membranes to protect the horse from respiratory diseases.

Neural System

When the cauda equina is pinched by the sacrum. The motor neurons that are pinched prevent the neural impulse from getting through to the muscles they innervate. The pain neurons that are pinched generate a neural impulse back to the brain that is perceived as pain. The horse usually has more pain and paralysis in one rear leg than the other. This causes the horse to pull the good rear leg more central to bear more of the horse's weight. When this happens the line of force is no longer down through the center of the hock. Instead the line of force is going through one side of the hock. This is the cause of hock problems. This also causes the horse to shorten the stride, and throw their weight forward, compounding the front leg problems.

Immune System

The immune system is greatly reduced by the continual secretion of adrenalin. The horse is more prone to microbial infections, parasites, and cancer. I believe EPM would not be a problem for a normal functioning immune system.

Hormonal System

The continual pain caused by the sacrum pinching pain neurons, causes the brain to secret hormones that activate the adrenal gland. This causes the continual secretion of adrenalin. Adrenalin in turn causes the thyroid to continually produce more thyroxin than normal - hyper thyroid - Cushings Syndrome. The thyroid gland eventually exhausts, and produces less than normal thyroxin - hypo thyroid - Addison's Disease. Other hormonal problems are seen in the reproductive system.

Digestive System

The continual secretion of adrenalin, greatly reduces the neural impulse, and blood supply to the digestive system. This can cause a host of problems:

Pancreatic Insufficiency

  1. Lowered production of enzymes for the digestion of food, and old connective tissues throughout the body.
  2. Lowered production of base fluids to neutralize stomach acids.
  3. Lowered production of insulin. This may be the cause of sugar diabetes in dogs.

Ulcers

  1. Over production of stomach acid.

Colic

  1. The reduced neural impulse to the digestive system slows down the motility (movement) of the intestines.
  2. The reduced blood supply to the digestive system caused the smooth muscles to spasm (Charlie Horse) due to the reduction in calcium.
  3. The low production of digestive enzymes allows the food ingested to putrefy and ferment. Fermentation causes excess gas production to occur. The gas builds up, causing the intestines to blow up like a balloon. The gas pressure eventually puts enough pressure on the veins bringing blood back to the heart, to shut them off. The arteries sending blood to the rear of the body resist the pressure. This causes most of the blood to be trapped in the rear, causing the horse to go into shock.
  4. The horse's weakened immune system allows the build up of blood worms in the arterial wall of the craniomesenteric artery, further reducing the blood supply to the digestive system.

I have relieved horses of colic by simply realigning the sacrum. This allowed the neural impulse, and blood supply to return to the digestive system. The increased blood flow brought more calcium to the spasmed smooth muscles, allowing the spasm to subside. The gas passed, and the fermentation stopped due to the increased levels of enzymes produced.

Reproductive System

Stallions have difficulty mounting due to the pain in their sacral area. The continual secretion of adrenalin greatly reduces the neural impulse, and blood supply to the stallion's reproductive system which affects sperm production. A new symptom discovered is paralysis of the penis. The penis hangs out of the sheath as if the horse were tranquilized.

Mares have difficulty bearing the weight of a stallion due to the pain in their sacral area. The continual secretion of adrenalin greatly reduces the neural impulse, and blood supply to the mare's reproductive system, causing hormonal problems. This causes the following:

  1. Cycling problems in the mare
  2. Lack of tone in the uterus
  3. Chronic uterus problems (see mucous membrane system, and immune system)
  4. Barren mares
  5. Reabsorbing/Passing of the embryo.
  6. Abortion

With the blood supply, and neural impulse reduced to the ovaries and uterus, if the embryo implants into the wall of the uterus, it will survive as long as it does not out grow the supply of nutrients being supplied by the mare's blood. Once it outgrows the nutrient supply, it will die and abort.

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Page updated Jan 25,2002 .