Cauda Equina Syndrome


  • Cauda Equina Syndrome: characteristic pattern of neuromucscular and urogenital symptoms which occurs due to the compression of multiple lumbosacral nerve roots below the level of the conus medullaris


  • Spinal Infection
  • Spinal Inflammatory Conditions
    • Ankylosing Spondylitis (see Ankylosing Spondylitis, [[Ankylosing Spondylitis]])
    • Chronic Inflammatory Demyelinating Neuropathy (CIDP) (see xxxx, [[]])
    • Paget’s Disease
    • Sarcoidosis (see Sarcoidosis, [[Sarcoidosis]])
  • Spinal Stenosis
  • Spinal Trauma
  • Spinal Tumors
    • Primary Spinal Tumors
    • Metastatic Spinal Tumors

Spinal Cord Anatomy and Physiology

Spinal Cord

  • Conus Medullaris: the spinal cord tapers and ends between L1 and L2, with the conus medullaris representing the most distal bulbous part of the spinal cord
    • Blood Supply
      • Spinal arteries (anterior median longitudinal arterial trunk and 2 posterolateral trunks): main supply
      • Radicular Arterial Branches from Aorta: less prominent arterial supply
      • Lateral Sacral Artery: less prominent arterial supply
      • Fifth Lumbar Artery: less prominent arterial supply
      • Iliolumbar Artery: less prominent arterial supply
      • Middle Sacral Artery: less prominent arterial supply
  • Cauda Equina (“horse tail”): mass of lower lumbar and S1-S5 nerve roots distal to the conus medullaris (and within the subarachnoid space)
    • Sensory Innervation: to the saddle area (perineal dermatomes) and lower extremity dermatomes
    • Motor Innervation
      • S2-S4 -> inferior rectal nerve -> voluntary muscles of external anal sphincter
      • S2-S4 -> pudendal nerve -> voluntary muscles of urethral sphincter
      • Lower extremity myotomes
    • Parasympathetic Innervation: to the bladder and lower part of the colon (from splenic flexure to the rectum)
      • S2-S4 -> pelvic splanchnic nerves -> detrusor muscle of bladder
    • Compression of the cauda equina technically represents a “peripheral” nerve injury
    • Blood Supply: middle sacral artery
  • Filum Terminale: the fibrous (non-neural) extension of the spinal cord, which extends down to the coccyx

Epidural Space

  • Posterolateral Epidural Space
    • Anatomy
      • Posterolateral epidural space extends vertically down the spinal canal and contains arteries, venous plexus, and fat
      • Posterolateral epidural space is larger than the anterior epidural space
      • Posterolateral epidural space is larger in the sacral region than it is in the cervical region
  • Anterior Epidural Space
    • Anatomy
      • Anterior epidural space is a virtual space under normal circumstances (due to adherence of dura to bone of vertebral bodies from the foramen magnum down to L1)



  • Areflexia
    • Ankle
  • Bladder/Bowel Dysfunction
    • Decreased Anal Tone/Fecal Incontinence
    • Urinary Retention: due to detrusor muscle weakness
    • Urinary Incontinence
  • Low Back Pain/Sciatica: sciatica may be unilateral or bilateral
  • Variable Lower Extremity Sensory/Motor Dysfunction
    • Lower Extremity Weakness: bilateral or unilateral
    • Lower Extremity Paraplegia: bilateral or unilateral
  • Saddle Anesthesia: involving genitals, uretha, anus, and inner thighs
  • Sexual Dysfunction


  • xxxx