One of the very first things taught at our school is the functions of the hoof capsule. We talk in terms of protection, support, suspension, and resistance, the hoof capsule has a multitude functions. One of the most important is to provide resistance to distortions induced by the stride. As an example, the wall of the toe must provide much more resistance to flexing than that of the wall at the heels. The primary reason is the task that it must complete during the stride, function is directly related to a structures foundation. The foundation at the heels is cartilage and at the toe bone.
The wall also helps in protecting the corium (sensitive, vascular tissue) that produces it, protecting against blunt trauma, infiltration of toxins, and prolapse (displacement) of the corium itself.
The most common form of corium prolapse associated with the hoof of the horse is a solar corium prolapse; where by the corium of the sole protrudes from the solar epidermis (horn). This sometimes happens when the horn of the sole is removed to expose an abscess, or following a puncture wound. Other areas of the hoof capsule that have been seen to host a prolapse, though not as common are the frog, and coronary band groove.
Why does the prolapse occur? As stated above, one function of the hoof capsule is to provide resistance. When this resistance is removed, either by injury or intentionally the risk of prolapse exist. Inflammation and instability are major contributors to the process of prolapse.
How can prolapse be prevented? First and foremost, anytime that corium or living tissue is involved, so to should the vet be involved. As a hoof care provider our work begins and ends with the hoof. Working with an attending veterinarian to prevent infection and reduce inflammation the hoof care provider can help in preventing the prolapse from occurring, by creating resistance where resistance has been compromised.
Resistance does not mean support; it means mild pressure that does not result in pressure necrosis (death of tissue).
I have attached photos of a case that involved a coronary band prolapse. This type of prolapse is not very common, but can occur when a large area of the coronary groove of the hoof capsule is lost.
This particular horse suffered an abscess which resulted in substantial loss of resistance at the coronary band. This foot was also very upright, and as a result a higher level of distortion occurred at the sight of the prolapse.
This was treated by providing resistance in the form of a Sole Mate Therapeutic Pad insert. The area was washed with Silvetrasol Hoof and Wound Wash, and the pad was fashioned to mirror the stratum internum (inner wall).
I then applied a Perfect Hoof Wear Poly Wrap to the foot, paying close attention to the amount of tension applied over the Sole Mate insert. The PHW Poly Wrap provided the resistance needed to prevent further prolapse, while the pad insert provided the stimulus needed for the development of healthy structure. The final picture was taken at four months from the onset of the condition. This package was applied four times.