The word cauda is Latin for “tail”. A syringomyeliaA cavity, within the spinal cord, which is filled with cerebrospinal fluid. Syringomyelia cavities come in various “shapes and sizes”, from short, spindle-shaped cavities through to long, tense cavities extending throughout the greater part of the spinal cord. See also hydromyelia. More cavity which is seen to enlarge progressively downward is expanding in a caudal direction.