Equine Cauda Equina Syndrome Study Guide

Overview and Clinical Importance

Cauda equina syndrome in horses, more accurately termed polyneuritis equi (PNE), is an uncommon but clinically significant neurological disease characterized by progressive granulomatous inflammation of the sacrococcygeal nerve roots and occasionally cranial nerves. First described by Dexler in 1897, this condition represents an immune-mediated polyneuropathy with pathologic similarities to Guillain-Barre syndrome in humans.

The term "cauda equina" derives from Latin meaning "horse's tail," referring to the bundle of spinal nerve roots extending from the caudal spinal cord. While this anatomical structure exists in all mammals, horses are highly susceptible to this specific inflammatory condition affecting these nerve roots.

Anatomical Foundations

The Cauda Equina in Horses

In horses, the spinal cord terminates at the sacrococcygeal junction (S2-S3 level), forming the conus medullaris. Distal to this point, the lumbosacral and coccygeal spinal nerve roots continue within the vertebral canal as the cauda equina, suspended in cerebrospinal fluid within the lumbar cistern.