Monday, November 17, 2014

X-rays beyond Balance

Do X-rays have value to the hoof care provider beyond referencing balance?

High exposure vs. Lower exposure, both have their purpose.
At our school we introduce students to “Physiological Sequencing”, an exercise that helps the hoof care provider understand the developmental process the foot has undergone. Physiological sequencing simply defines how the foot undergoes change in response to a change in stimulus. It is understood that within the foot there are several types of tissue, with the definition of a tissue being: A tissue is a collection of the same cells with the same characteristics, size shape and arrangement. Tissue is a component of the whole organism and carries out a specific function.
In the horse’s foot the first tissue to show physical change in response to a change in stimulus is soft tissue, that tissue which is vascular (having blood and nerves), the second tissue to show a physical change is classified as Dynamic. Dynamic tissue is avascular tissue such as horn and cartilage. Hoof wall flares, false sole, changes in cartilages are all examples of changes to dynamic tissue. The last tissue that we observe physical change in is bone. Bone, though we understand that bone is always undergoing change, we as hoof care providers need to understand that by the time we observe physical change in bone, a sequence of events has occurred involving soft and dynamic tissue.
Why have I spent time explaining physiological sequencing on a post about x-rays, because x-rays can better be used by the hoof care provider to develop an understanding of what chronic conditions may be present and responsible for the picture presented by a given x-ray.
The farrier cannot be expected to treat or balance the hoof of the horse if they do not understand the current state of health of the supporting structures of the hoof, the foot’s very foundations. The hoof care provider should be able to view an x-ray and be able to interpret how that horse has been loading a given foot, and even how it has been traveling. Bone health and remodeling is a response to a stimulus, and that stimulus is created when the horse moves.
There is an exercise that I use to help in developing a student's eye. I have attached two power points. One is a series of x-rays, the other a series of hoof photographs. The link is to a quiz that challenges you to match the hoof to the appropriate x-ray. The key is to develop your eye in seeing the true foundations of the foot you are working on. Do not concentrate on bone only; observe the conformation of the cartilages of the caudal foot.
In order to be successful in taking this quiz you will need to understand the basics of radiographs.
  1.  Though radiographs can appear three dimensional, you must remind yourself that they are two dimensional, and that interpreting density is the task at hand. Mutiple views are needed to create a three dimensional image.
  2. Beam direction is irrelevant. Whether the beam is medial to lateral or lateral to medial the image appears the same.
  3. Understanding exposure is crucial. High exposures are reserved for deep structures, such as the navicular bone. Lower exposures used when viewing the distal border of the pedal bone, or to outline the bones of the foot for balance.
  4. Incorrect exposure can lead to false readings when trying to implement physiological sequencing. Example: A solar margin view (distal border of P3) taken at a high exposure will result in an image that could be interpreted as P3 having bone loss (rarefication).
  5. Oblique views (angles) are used to define margins.
  6. Oblique views are intentional, Lateral/Medial (LM) and Dorsal/Palmar (DP) views are often presented to the farrier for purpose of balance, they should not be presented on an oblique.
I  spend more than 140 hours teaching physiological sequencing to our advanced level students enrolled in our level two program. . X-rays can be extremely helpful in developing a hoof treatment protocol, way beyond simply balancing of the hoof. This is not diagnosing, it is learning.






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