Brown-Séquard Syndrome


Brown-Séquard syndrome is an incomplete spinal cord injury, affecting the entire lateral half of the spinal cord (hemisection) and results in weakness or paralysis on one side of the body and a loss of sensation on the opposite side

Brown-Séquard Syndrome results in weakness/paresis and loss of fine touch, proprioception and vibration sense ipsilaterally below the lesion, and loss of pain and temperature sensation contralaterally, beginning one to two levels below the lesion.

Classic presentations are uncommon, and often presents as asymmetrical hemiplegia and reduction of pain sensation that is more prominent on the less paretic side.

Overall, the condition is rare, making up 1-4% of all spinal cord injuries, and most commonly in the context of penetrating trauma. The cervical cord is the most common region affected. Rarely, occurs as a result of blunt trauma, disc herniations, fractures, tumours or haematoma


Lateral corticospinal tract decussates at medulla oblongata, and after decussation only innervates muscles of the ipsilateral side. Right-sided primary motor cortex output passes through and crosses at the medulla oblongata, and travels down the left-sided lateral corticospinal tract in the spinal cord

  • Weakness/paresis ipsilaterally below the level of the lesion

Dorsal column travels ipsilaterally up the spinal cord, and then crosses over at the lower medulla

  • Loss of fine touch, vibration and proprioception ipsilaterally below the level of the lesion

Spinothalamic tract, which is responsible for the transmission of pain and temperature sensation, enters the spinal cord and then crosses over 1-2 levels above, still within the spinal cord

  • Loss of pain and temperature sensations beginning 1-2 levels below the lesion of the spinal cord
Diagnosis and Prognosis

MRI shows enhancement/lesion of the lateral half of the spinal cord (hemisection)

Overall prognosis is good, and has the best functional outcome compared to other spinal cord injuries. However, the classic presentation of Brown-Séquard syndrome confers a worse prognosis.

Most patients have normal bowel and bladder continence

History of Brown-Séquard syndrome

1849 – Brown-Séquard writes an article describing his experiment of cord hemisection in a guinea pig and describes the clinical syndrome.

  • Cut the right lateral half of the spinal cord in the cervical region of a guinea pig
  • Found that there was incomplete paralysis of the right side
  • Sensation was intact if not exaggerated on the right side
  • Tenderness on the right side but not on the left side
  • Concluded that the anterior columns (motor function) were also transmitted in a crossed-fashion above the spinal cord

1853 – In his textbook Experimental researches applied to physiology and pathology, Brown-Séquard discusses the loss of temperature sensation on the contralateral side to the hemisection of the spinal cord. He restated that the motor function ipsilaterally below the lesion was impaired.

1869 – Brown-Séquard published another article in The Lancet, once again regarding the effects of complete hemisection of the lateral cord, stating three key findings.

  • Paralysis of voluntary movements on the same side
  • Anaesthesia to touch, tickling, painful impressions, and changes of temperature of the opposite side.
  • Paralysis of the muscular sense on the same side

1892 – English neuropathologist Frederick Walker Mott (1853-1926) challenged Brown-Séquard’s notion that below the level of the lateral hemisection, there would be ipsilateral hyperaesthesia. Mott’s experiments on monkeys showed that there was ipsilateral loss of sensation below the lesion, and contralateral preservation of pain sensation

While engaged in studying experimentally the connections of the cells of Clarke’s column with the ascending tracts of the spinal cord in the Monkey, I was surprised to find that after hemisection in the lower dorsal region, the sensory disturbances produced in no way corresponded with those already obtained by an eminent observer.

Mott FW, 1892

1894 – Brown-Séquard responds to Mott’s paper and states that he revisited his experiments and original paper, and agreed that there would be ipsilateral loss of sensation below the level of lateral hemisection, but contralateral loss of pain and temperature sensation

1894 onwards – modern description and widely accepted clinical syndrome of lateral hemisection of the spinal cord, eponymously named Brown-Séquard syndrome. Findings consistent through many case reports

Associated Persons

History of the Syndrome
Brown-Sequard Syndrome



the names behind the name

Final year MBBS student at Curtin Medical School. Keen interest in internal medicine and neurology, medical education, and integrating specialist healthcare into rural medical practice.

BA MA (Oxon) MBChB (Edin) FACEM FFSEM. Emergency physician, Sir Charles Gairdner Hospital.  Passion for rugby; medical history; medical education; and asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | Twitter |

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