In the roll call of neurological diseases from which horses can suffer, there is one many horse owners don't yet know about–cauda equina syndrome. Caused by myriad infectious, inflammatory, and/or traumatic factors, the syndrome includes many hind-end neurological clinical signs stemming from damage to the cauda equina, the tapered end of the spinal cord along with the extensions of spinal nerve roots extending alongside and past it. Scott Pirie, BVM&S, PhD, CertEP, CertEM, MRCVS, described cauda equina syndrome in depth at the 2004 British Equine Veterinary Association Congress, held Sept. 15-18 in Birmingham, U.K.

Postmortem specimen of the cauda equina region from a horse with cauda equina neuritis (polyneuritis equi). As a result of the inflammation associated with this condition, the sacrococcygeal spinal nerve roots (one of which is highlighted), seen emerging from the dura covering the terminal spinal cord, are markedly swollen.

Courtesy Professor I.G. Mayhew

"The cauda equina is so called due to its gross resemblance to a horse's tail," he began. "The most common clinical signs of cauda equina syndrome include tail paralysis/weakness, anal hypotonia/atonia (poor or no muscle tone), rectal and bladder paralysis/weakness, and relaxation and protrusion of the penis. Other signs include lack or absence of skin sensation (hypalgesia or analgesia) of the tail, anus, and skin of the perineum; and muscle atrophy of the coccygeal muscles (which control tail movement). Occasionally, hindl