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Cauda Equina

cauda equina

The cauda equina (horse's tail) is the collection of nerve roots below the conus medullaris that float freely in CSF within the lumbar and sacral thecal sac, descending to exit through their respective intervertebral foramina. It consists of the L2-S5 nerve roots in pairs. The roots are arranged with the most caudal roots (sacral) most centrally and the upper lumbar roots peripherally within the thecal sac.

Region: Lower Back

Clinical Relevance

Clinical Notes

Cauda equina syndrome (CES) is a surgical emergency caused by compression of the cauda equina by massive disc herniation, tumour, haematoma, or epidural abscess. The clinical syndrome includes bilateral leg weakness, saddle anaesthesia, and loss of bladder and bowel control (overflow incontinence or retention). Emergency decompression within 48 hours of sphincter dysfunction onset is associated with significantly better outcomes. MRI of the entire lumbar and sacral thecal sac is essential for diagnosis and surgical planning.

Pathology

Common Injuries & Conditions

Cauda Equina Syndrome

Acute compression of the cauda equina by a massive L4-L5 or L5-S1 disc herniation or other compressive lesion produces bilateral leg weakness, saddle anaesthesia, and urinary retention or overflow incontinence requiring emergency MRI and surgical decompression within 48 hours to maximise neurological recovery.