Some website and magazine editors have asked for a treatment of orthopedic and non-orthopedic spinal disorders, specifically the syndrome (meaning a collection of symptoms) called cauda equina or CES. While not all involve bones and articulating joints directly, there are several problems that yield symptoms that could be mistaken for those of HD (or other disorders that produce lameness) and the miscellaneous vertebral malformations that compress the spinal cord.  Several, including dural ossification, are mentioned in the chapter on spinal disorders in my up-coming book on canine orthopedic disorders.  Three are discussed in this article, although CES might actually comprise several disorders instead of just one.