26/06/2026
LAMINITIS
I completely agree. I think this is one of the most interesting aspects of laminitis because we often concentrate on what the pedal bone is doing, but the changes occurring at the coronary groove explain why the hoof itself begins to change shape over time.
Even a drop of only a few millimetres can have profound consequences within such a small structure. Once the lamellar attachment can no longer suspend P3 in its normal position, the coronary corium is displaced. The cells responsible for producing the hoof wall continue to divide and produce horn as they always have, but because the tissues producing that horn are no longer correctly aligned, the horn tubules are formed in a different orientation.
That change in orientation is what gradually alters the shape of the hoof capsule. Rather than growing down in its usual alignment, the hoof wall begins to follow a different path. Over time this results in the characteristic growth rings, changes in hoof wall angle, flaring and, in more advanced cases, the classic slipper foot appearance. The hoof wall is effectively preserving a record of the altered biomechanics occurring within the foot.
It is remarkable that by simply examining the outside of the hoof, we are often looking at a timeline of the pathological events that have taken place internally.
For anyone wondering what this means in simpler terms, imagine the pedal bone is suspended inside the hoof by thousands of tiny Velcro-like attachments. During laminitis those attachments become damaged, allowing the bone to sink slightly. As it moves, it changes the position of the tissues at the top of the hoof that grow the hoof wall. The hoof continues to grow, but it is now growing from tissue that has shifted position, so the new hoof is laid down at a different angle. That is why the hoof gradually changes shape and develops the growth rings that are so commonly associated with laminitis.
When P3 Drops: What Happens at the Coronary Groove?
One of the things I find interesting in laminitis cases is what happens at the coronary groove when P3 loses its normal suspensory support and begins to descend within the hoof capsule.
In this sagittal section, you can see the soft tissues of the coronary region changing shape as P3 drops. The P3 drop is approx 3 mm. Not a lot but it makes a HUGE issue inside the foot.
The first part of the hoof wall is quite soft. It becomes harder as it is keratinised as the cells are pushed down. Keratinisation occurs about 3 mm from the edge of the coronary groove.
As P3 drops:
The lamellar attachment can no longer maintain the normal position of the bone within the capsule.
Body weight and gravity wins….
The entire bony column moves distally (downwards) relative to the hoof wall.
Soft tissues within the coronary groove become distorted. They are dragged down as P3 drops.
Horn produced at the coronary groove will change direction, producing the characteristic growth rings often seen in chronic laminitis. Look at the kinks in the tubules in this specimen. That would cause a big growth ring has the horse survived this catastrophic laminitis. In this case it’s thoughts to be due to an antibiotic administered that caused massive colitis.
The growth rings are not simply “rings.” They are a record of changing biomechanics within the foot. The horn is being generated from a coronet that is no longer occupying its normal anatomical position. The cells continue to divide but their orientation is in the wrong place.
LIndsey Field.
