Equine Neurological Dysfunction

brain and spinal cord whereas the peripheral nervous system PNS is an umbrella term for all of the nerves in the body. These nerves transmit information between the CNS and the other body parts such as the skin muscles and internal organs.
2 Cranial vs. Spinal Nerves The PNS is further divided into cranial nerves which arise from the brain and spinal nerves which originate from the spinal cord. The cranial nerves mainly provide innervation to the head but also extend to the internal organs such as the heart and digestive system. The spinal nerves are responsible for innervation of the rest of the body including the limbs and trunk.
3 Motor vs. Sensory Nerves All cranial and spinal nerves of the PNS are categorized as either motor or sensory nerves. Motor nerves relay information from the CNS to the body and cause contraction of muscles resulting in movement. Sensory nerves gather information from the body and environment and provide this information to the CNS. For example if a horse steps on a stone sensory nerves relay information about this painful event to the CNS which promptly stimulates the motor nerves to make the horse move his foot away from the stone.
When presented with a horse with suspected neurological disease a veterinarian must use his or her knowledge of the anatomy of the nervous system in order to pinpoint the area that has been injured. For instance if a horse shows signs of neurological deficit in both of his hind limbs it is much more likely that the horse has a problem in his spinal cord CNS than two separate injures in the spinal nerves PNS of both hind limbs. Once the anatomical location of the injury has been determined further testing can be conducted to find out which disease is causing the observed problems.
A multitude of potential hazards to the equine nervous system exist. Some causes of neurological disease include physical trauma genetic and developmental disorders toxins parasites infectious disease nutritional imbalances and tumours. Depending on the case a veterinarian may recommend medical imaging such as radiography blood testing for infectious diseases or toxins or collection of cerebrospinal fluid for analysis. Sometimes the problem can be diagnosed on a physical examination alone. With an accurate diagnosis a treatment plan and prognosis can be developed for the horse. 
A Tale of Two Neurological Cases
The following case studies are meant to help illustrate