Sequence of Events During Laminitis

In the normal healthy hoof the sensitive and insensitive laminae provide a tight bond between PIII and the hoof wall. The laminae transfer most of the horse's weight from the skeleton to the hoof wall upon which he stands. At rest gravity is the main force acting on the lamellar bond. In motion, the pulling force of the Flexor Tendons is added to gravitational force. Trimming the hoof's toe as short as soundness allows and using a Rocker Toe Shoe reduces the length of the lever arm against which the Flexor Tendons pull. Depending on individual conformation, this can reduce hoof stress substantially. Any reduction in hoof stress is valuable to the sound or laminitic horse.

During laminitis the laminae become inflamed. Inflammation is accompanied by edema (the attraction of intercellular fluids). There is a fixed fluid volume within the lamellar space. As edema collects, it displaces some other fluid; blood. If this process continues blood is displaced until insufficient blood flow exists to maintain life in the sensitive (live) laminae. The pressure caused by edema is also felt by the lamellar nerves, producing pain (this is not yet the pain from lamellar tearing). The pain level is indicative of the edemic pressure level. It should be noted that the "Stoic" horse will show less pain than will the "Weenie" horse. The laminitic horse becomes the foundering horse when insufficient of blood flow allows lamellar tissue to die,causing the lamellar bond to fail.

These early events can be called the Developmental stages of founder. Prior to the death of sensitive lamellar tissue, the lamellar bond is weakened. At this stage the laminae can stretch just enough to allow PIII to descend slightly, crushing capillaries in the solar corium below. Blood leaking from the crushed capillaries produces stains seen in the sole horn called "symmetrical subsolar hematomas". Similar stains may also be seen in the White Line. Because lamellar stretching can occur prior to the lamellar tearing associated with founder, red white line and/or symmetrical subsolar hematomas can be present while the horse is still in the laminitic stage. In the case of the "Stoic" horse, these hematomas can appear with very little evidence of pain. Red white lines and symmetrical subsolar hematomas are important symptoms of laminitis and should not be ignored or confused with "Stone Bruises". The reverse is not true: A horse may be fight on the verge of foundering and show no signs of these stains.

Once the laminae begin to die, the potential exists for rapid deterioration. At this point PIII will either rotate, sink, or both. This is "Founder" or "Acute laminitis". As the laminae are pulled apart the space created by the tearing may be filled with blood, serum, pus, or general gick. This is called the "lamellar wedge" This wedge must be removed before PIII can be replaced to it's proper location. Now the horse has lost his opportunity for a scar free recovery without human intervention.

Heart-Bar Shoe

If the heart-bar shoe is applied BEFORE laminitis allows PIII to drop, the pressure bar (located under the blue dot) will prevent PIII from dropping.

Figures 1 and 2 are the same drawing, with some color added to fig.2. I did this on purpose to illustrate that radiographic evidence of developmental laminitis may be difficult to determine. Don't look for gross changes to initiate therapy. Though radiographic evidence may be seen in early laminitis, it is not necessary for a diagnosis. If laminitis is suspected, pain alone is sufficient cause to support PIII. When I work with a laminitic horse I judge the efficacy of my therapy against the comfort of the horse.

I fit a rim shoe to the foot just as I would normally do. With the shoe held against the foot I mark the shoe as per the crosshairs in the figure. I use these marks to locate the tip of the pressure bar for welding, adjust the height of the bar, and apply the shoe, and chanjo presto, the horse is fixed(in your dreams).

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