I: The Healthy Spinal Cord

This first paper aims to review our current understanding of the structure and function of the normal equine spinal cord and its associated vertebral column, beginning with the latter. Because of their intimate relationship, an understanding of these two structures is vital for localising signs of spinal cord disease particularly as many spinal cord disorders involve changes in the vertebral column. Clinically relevant aspects of vertebral and spinal structure and function that are important to the neurological examination will be highlighted. A plea is made here to use correct anatomical terminology1 as detailed in Nomina Anatomica Veterinaria.2 Importantly, ‘‘backbone’’ and ‘‘spine’’ are human terms and are not used; ‘‘vertebrae’’ and ‘‘vertebral column’’ are appropriate animal terms and are used. Also, the terms ‘‘dorsiflexion’’ and ‘‘ventroflexion’’ are hackneyed and incorrect. The correct terms to be used are ‘‘extension’’ (or ‘‘lordosis’’) and ‘‘flexion’’ (or ‘‘kyphosis’’) of vertebrae. Finally, little will be said of ancillary aids, because these will be covered within the specific disorders presented in part II. 2. The Vertebral Column