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
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
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)
Clinical
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