What are the signs and symptoms of cauda equina and conus medullaris?

Updated: Jun 14, 2018
  • Author: Segun Toyin Dawodu, JD, MD, MS, MBA, LLM, FAAPMR, FAANEM; Chief Editor: Nicholas Lorenzo, MD, CPE, MHCM, FAAPL  more...
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Patients can present with symptoms of isolated cauda equina syndrome, isolated conus medullaris syndrome, or a combination. The symptoms and signs of cauda equina syndrome tend to be mostly lower motor neuron (LMN) in nature, while those of conus medullaris syndrome are a combination of LMN and upper motor neuron (UMN) effects (see Table 1, below). The history of onset, the duration of symptoms, and the presence of other features or symptoms could point to the possible causes.

Table 1. Symptoms and Signs of Conus Medullaris and Cauda Equina Syndromes (Open Table in a new window)


Conus Medullaris Syndrome

Cauda Equina Syndrome


Sudden and bilateral

Gradual and unilateral


Knee jerks preserved but ankle jerks affected

Both ankle and knee jerks affected

Radicular pain

Less severe

More severe

Low back pain



Sensory symptoms and signs

Numbness tends to be more localized to perianal area; symmetrical and bilateral; sensory dissociation occurs

Numbness tends to be more localized to saddle area; asymmetrical, may be unilateral; no sensory dissociation; loss of sensation in specific dermatomes in lower extremities with numbness and paresthesia; possible numbness in pubic area, including glans penis or clitoris

Motor strength

Typically symmetric, hyperreflexic distal paresis of lower limbs that is less marked; fasciculations may be present

Asymmetric areflexic paraplegia that is more marked; fasciculations rare; atrophy more common



Less frequent; erectile dysfunction that includes inability to have erection, inability to maintain erection, lack of sensation in pubic area (including glans penis or clitoris), and inability to ejaculate

Sphincter dysfunction

Urinary retention and atonic anal sphincter cause overflow urinary incontinence and fecal incontinence; tend to present early in course of disease

Urinary retention; tends to present late in course of disease

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