A vertebral canal that is too small for the diameter of the spinal cord could easily be caused by nutritional hypercalcitonism. Calcitonin is released from the thyroid gland when the animal is fed a diet high in calcium. Its function is to retard bone reabsorption and thus decrease blood calcium levels. Remember, calcium is kept within strict limits in the blood stream. In normal growth, expansion of the spinal canal must be perfectly synchronized with growth of the spinal cord.
Expansion is achieved by resorption of bone inside the vertebral canal.
With hypercalcitonism, the retarded rate of bone resorption prevents proper expansion of the canal - therefore the diameter of the spinal canal is decreased and has an irregular contour. The spinal cord grows independently of the surrounding bone and is thus pinched by the nonresorbed bone therefore causing Cervical Spondylopathy. Nerves leave the spinal cord, to go to other parts of the body, through spaces formed by notches is the vertebrae called foramina. A narrowness in these spaces will cause a pinching of the nerves leaving the spinal cord which in turn causes inflammation and swelling of the spinal cord itself thus causing wobblers syndrome. Hypercalcitonism causes narrowness in the vertebral canal can also yield a stenosis of the cranial orifices of the vertebral foramina due to its effect of slowing bone resorption.