Imaging of the Equine Neck With a Focus on Vertebral Variation and the Intervertebral Disc

The equine neck contributes to the balance of the horse, both by its direct biomechanical
function as the lever of the head and by transmitting the processed sensory input of
the eyes, ears and vestibulocochlear system from the brain to the trunk and limbs. It
therefore plays a major function in the total movement pattern of the horse. Modern
horse breeds are mostly deployed for equestrian sports. Body conformation and
functional characteristics of horses have changed tremendously since domestication
started about 6000 years ago. With it a decline in genetic diversity has been
recognized, influencing amongst others a part of the genes that is responsible for the
embryonic development of the vertebral column, known as the HOX or Homeobox
genes. Changes can cause variation in shape and size of the vertebrae. About one third
of Thoroughbred and warmblood horses have shape variations of the two last neck
vertebrae.