Cauda equina

NervousOrgansWhole body

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What it is

The "horse's tail": the bundle of lumbar, sacral and coccygeal nerve roots (L2-Co1) that stream down the dural sac below the end of the cord to reach their exit foramina.

Function

Carries motor and sensory fibres for the legs, bladder, bowel and genitals.

Size

About 20 pairs of roots filling the lumbar dural sac from L1/L2 to S2 (~15-20 cm)

Clinical note

Compression by a large central disc herniation (cauda equina syndrome) causes saddle numbness and bladder retention - a surgical emergency.