What are sensitive Laminae?

Everyone knows that horses can be prone to attacks of laminitis because of rich grass.  But what actually are the sensitive laminae in the feet.

Compared to humans, horses stand on ’tip-toe’ like a ballerina. More exactly, horses only stand on one toe and the other toes, which humans have, do not exist in the horse. The nail of the one remaining horse’s toe has changed to make the hoof and the other toes are only seen in the form of splint bones higher up the leg (See P 60 in the catalogue).

So where do the laminae fit in? You can imagine that there is a lot of pressure on a horse’s feet because of the way it stands on ’tip toe’. Although the hoof is very strong and large there needs to be some special way of fixing the toe inside the hoof if this is to be a comfortable way of standing.

One of the ways horses legs are able to cope with this situation is by having sensitive and insensitive laminae layers which fix the toe in position inside the hoof. Microscopically these layers both look like corregations of corregated cardboard and fit firmly together to give great strength. The insensitive laminae are part of the hoof wall and sensitive laminae are made up of blood vessels and nerves which are bound to the soft tissue and the ’toe bone’ beneath. In this way the bone of the foot is firmly attached to the tough hoof wall. In horses prone to laminitis the sensitive laminae are prone to damage from toxins released from undigested grass in the gut. These toxins pass through the blood.