Below is an extract from a Facebook page which I am a 'fan' of. I noticed some comments were posted about a picture of a cross section of a hoof which looked like it had had equine digital elastosis and laminitis. There were comments which lead me to believe the writer niaively dismissed the coronet band as relevant in functionality. This was my response which I think was over the too over the top but it is really hard to write in a concise manner as the topic is actually quite in depth. I thought it was interesting enough to post here too but it has made me more determined to try and help people learn more about correct anatomy and physiology of the foot and the improtance in proper education amosgst horse owners, farriers, vets and most importantly, hoof care providers (which are all terribly keen; like me, in spreading the word about barefoot hoof care!).......
The question asked of me was this; could I explain dynamic equilibrium and the the role of the coronet band in laminitis.....
Dynamic equilibrium is defined (in applied equine podiatry or AEP) as all structures functioning optimally at any given moment in time which is required for PERFORMANCE. Performance is achieved when each structure is capable of SUSTAINING dynamic equilibrium of functions for the demands asked of it. So dynamic equilibrium can only occur in a system with each component doing what it is supposed to do at each moment in time. So when one structure suffers, it falls out of dynamic equilibrium and the horse loses performance in the foot.
It is imperative that as hoof care providers, we are very clear in our mind an understanding of the structures and their role in achieving dynamic equilibrium. All too often, trimmers search for the 'how to trim' rather than asking 'why do we trim'.
So, every structure in the foot has a FUNCTION (either protection, physical support, physiological support or suspension), which determines its PERFORMANCE which is either energy utilisation or energy dissipation. The Coronary band has an important functional role to play both in haemodynamics and in its role within the internal ach apparatus, or IAA. Firstly, think of its structure; it is an incredibly strong tissue which terminates half way down the frog, has papillae to grow the hoof wall and sits conveniently within the coronary groove within P3. Now think of its foundation (what does it rely on for its support). Its foundation at the front of the foot is bone (static tissue) and its foundation at the back of the foot is cartilage (also static tissue but can be manipulated to change more readily than bone and thus behave more like dynamic tissue). In its role in foot haemodynamics (or blood flow and energy utilisation) it has a role in protection as it allows for distortion but creates variable resistance. However, its primary role is in physiological support as it acts like a tornique at the end of pastern descent during movement (but not quite shutting off the supply of blood). So with regards its role in haemodynamics, its primary performance role is energy utilisation.
The coronary band is part of the IAA and is a part of the suspension of the internal arch within the hoof capsule and it does this by growing the hoof wall. So its primary functional role is considered suspension and its primary role in performance is energy utilisation (as this is what the IAA does). To fully understand the IAA and how the foot functions as a whole BEFORE one discusses laminitis, please read at least this paper: http://www.appliedequinepodiatry.org/Text_Files/Energy_Managemen_Article.pdf
So the lamellae are not responsible for holding the internal foot inside the hoof capsule. The internal arch apparatus or IAA is within dynamic equilibrium. Conventional veterinary medicine targets laminar to hoof wall integrity as being the predisposing factor in laminitis and the deformities associated with it (stretched white line, high heels, laminar horn etc). However, AEP recognizes the subtle changes taking place in the suspensory and supportive foundations of the caudal foot. So together with changes in the lateral cartilages, come changes in the conformation of the coronary band. The focus of the cause of rotation is no longer lamellae integrity but instead falls upon the deformation of the ungular cartilages; the foundation responsible for the support and suspension of the coronary band and ultimately the IAA within the hoof capsule. This is due to a loss of elasticity due to metabolic imbalance (from a variety of causes) which affects those soft tissues which make up a portion of the IAA (tendons, ligaments, coronary band, etc). The loss of integrity of lamellae to horn is a secondary condition to elastosis although mechanical stresses created by the same enzymatic action affecting the support and suspensory structures of the caudal foot, result in mechanical separation.
So in discussing laminitis and treating it correctly, one must ask the right questions. What is the root cause? What is the pathophysiological sequence of events which ultimately lead to laminitis and how can we support healing? As a DAEP, due to an in depth understanding of the structures and tissues and functionality of the internal foot and what is required for performance, I apply my knowledge and aim to stem the change in conformation of the ungular cartilages long enough to see stabilisation in faulty metabolic processes and thus avoid separation and rotation. The tools we tend to use are sole mate pads and perfect hoof wear wraps and of course the high performance trim method; all of which are aimed at providing appropriate environmental stimulus to allow for the return of health (which in some extreme circumstance may not mean a return to high performance) DAEP’s also adopt a holistic view and seek to understand the cause of the elastosis and advise management changes as appropriate.
There is LOADS to be gained and nothing to be lost by reading the following paper: http://www.appliedequinepodiatry.org/Text_Files/EDE_Paper_Sept_2010.pdf I advise anyone remotely interested in horses hooves, be it in natural barefoot trimming or conventional farriery to attend a 5 day IAEP course which is very intense and thorough on theory. Details can be found here: http://www.appliedequinepodiatry.org/iaep/index.html More info also on my site: http://www.holisticequineservices.co.uk/ and my facebook page: Holistic Equine
Thanks for the questions!