Cauda equina

Last revised by Yahya Baba on 7 Oct 2021

The cauda equina is the collective term given to nerve roots distal to the conus medullaris, which occupy the lumbar cistern

Its name comes from the Latin for "horse's tail".

The cauda equina is contained within the thecal sac and suspended in CSF. The lower sacral (S2-S5) and coccygeal roots are located in the dorsal aspect of the sac, whereas the lumbar and first sacral roots lie obliquely as they descend.

The nerves of the cauda equina supply innervation to pelvic organs, internal and external sphincter, perineal sensation, and the lower limbs.

Blood supply comes from the anterior and posterolateral spinal arteries as well as radicular branches from segmental arteries.

Related pathology

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Cases and figures

  • Figure 1: cauda equina (Gray's illustration)
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  • Case 1: cauda equina on sagittal T2W
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