When a horse has laminitis this laminar attachment becomes inflamed and swollen. As there is no space between the bone and the hoof wall for this swelling then pressure builds up and the result is a pounding pulse and pain.
If the laminitic horse has badly shod or trimmed feet or long-toed feet that are flared and stretched away from the bone, the horse will have additional pain caused by the outward tugging of long toes. So it is very important to remove any hoof wall that has pulled away from the bone. (This is sometimes seen as a trumpet or bell shaped hoof) When this is done you can deal with the primary pain in the laminae.
The bone inside the hoof is called the pedal bone (in the US it's called the coffin bone, also the P3, or distal phalanx) and it is shaped like a miniature hoof. Underneath the bone is the hoof sole, similar to the sole of a leather shoe.
The large V shape in the back of the sole area (see below) is the frog and it has many functions but since this article is about laminitis the sole / frog discussion can be the subject for another time.
The pedal bone is protected below by the sole/frog and along the front and sides it is protected by a thick shell of hoof wall all the way from the toe to the heel and up to the coronary band.
At this point it is necessary to understand that what is normally referred to as the hoof is merely a thick shell attached to the pedal bone. This hoof wall grows down from the coronary band and is attached to the bone by vertical stripes called Laminae. These stripes are like velcro and like velcro have inner and outer layers.
The layer closer to the bone is sensitive and has a very complex blood supply. The outer layer is insensitive and has no direct blood supply. These two layers lock together and hold the hoof wall to the bone. This is the laminar attachment and it needs to be strong to hold the pedal bone in position.
Types of Laminitis
Laminitis has different triggers; technically it can be systemic, concussive or stretch. No matter what the type or cause, the result is always inflamed laminae under the hoof wall.
Systemic Laminitis is when the laminae become inflamed due to a chemical reaction within the horse’s system ( the actual cause of this reaction in some horses and not others is still unclear). Examples might include if a horse got onto rich grass high in sugar and carbohydrates - some horses react badly to this responding with severe inflammation in the feet. Other examples would be infection in the body due to placenta retention after foaling, or any other infection in the body. Any build up of toxins for any reason can cause laminitis.
Concussive Laminitis is when a shod horse is working on hard ground and he hammers his shod feet until everything becomes inflamed. This affects feet only and can usually be managed by deshoe, proper trim and rest.
Stretch Laminitis is when the toes have been allowed to grow long and flared and they simply tug and pull on the laminae until the laminae become inflamed. Again this is feet only and can be managed by a proper trim and rest.
In many cases there is a combination of systemic and stretch, the systemic laminitis cannot heal until the stretch is dealt with.
This horse is clearly in pain, due to Laminitis -
please view our gallery to see a similar photo and the outcome after one quick treatment.
The video below shows 'a pony in treatment', photos of his feet when he arrived with us are also available to view in our gallery.
(To view in large screen, click the arrow box to the left of vimeo)
For further information on Navicular Syndrome, we suggest you look at this paper from Dr. Tom Teskey 'The Unfettered Foot' which we believe is definitive.
Watch here to see how to catch laminitis early: http://www.youtube.com/watch?v=QS-7ZaaZj8E&sns=em
Some images used here are courtesy of www.thenaturalhoof.co.uk