In my farrier work, I sometimes come across cases of lameness that are difficult to diagnose. I have come to believe that laminar strain, often associated with uneven weight bearing, is the cause of many of these concerns.
When it comes to functional anatomy, the lamina are responsible for the connection between the hoof wall and the coffin bone (third phalanx).
The sketch shown here represents a cross-section of the horse’s foot where ground reaction forces (GRF) and forces due to mass are balanced by healthy lamina.
The hoof wall lamina can be divided into dermal and epidermal lamina and dermal tissue can be divided into primary (Figure 1) and secondary lamina. However, the secondary dermal lamella can only be visualized with a microscope.
Figure 1: Primary dermal lamella can be divided into primary and secondary lamina.
Figure 2: Along with the dermal lamia, the epidermal lamella offer a shock-absorbing connection between the coffin bone and the horn capsule.
Figure 2 shows the epidermal lamella (L). The two types of lamina together offer a shock-absorbing connection between the coffin bone and the horn capsule.
Figure 3: The sensitive lamina and horn laminae interlock much like a zipper.
The sensitive lamina and the horn laminae interlock much like a zipper (Figure 3). Together, they create a strong bond in a healthy foot that can withstand up to 400 pounds per square inch of tension before separating.
Lameness can be a problem when the disconnected area of the…