Past Papers · SAQ

Neural Pathways — Brown-Séquard

Current · V5 (2025) → H1.iv Historical · V4 (2023) → K1.v 1 exam appearance

2008B Q08

Exam question

Describe the clinical findings you would expect to see in a patient who underwent acute hemi-section of the spinal cord at the upper thoracic level.

CICMWrecks answer

Master answer

Spinal Cord Tracts:
(not a comparison table)

Ascending Tracts
SENSORY

Descending Tracts
MOTOR

Convey sensory info from peripheral sensors to higher centres in brain.
From posterior to anterior:

Carry motor information

  • Dorsal (posterior) column:
    • fine touch + proprioception + vibration
    • crosses at the brain stem
  • Spinocerebellar tracts (ant + post):
    • Carry proprioceptive info from muscles + joints to cerebellum
    • Does not cross
  • Lateral spinothalamic tracts
    • pain + temperature
    • Crosses within 2 vertebral segments
  • Anterior spinothalamic tracts
    • crude touch + pressure
    • Crosses within 2 vertebral segments
  • Corticospinal tracts (ant + lateral) “pyramidal tracts”:
    • motor function – carry axons of UMN
    • crosses at the brain stem
    • Relay to alpha-motor neurons (LMN) in ventralnhorn of spinal cord
  • Extrapyramidal tracts:
    • rubrospinal, tectospinal, vestibulospinal, olivospinal, reticulospinal
    • Originate in brainstem nuclei and do not pass through medullary pyramids
    • Role in control of posture + muscle tone
Diagram used in Neuro – Pathways — Master Answer
Source: Diagram used in Neuro – Pathways — Master Answer · Source/permission verification pending.

Acute hemi-section of the spinal cord at the upper thoracic level

Brown-sequard syndrome: Hemisection of the cord

Diagram: Brown-sequard syndrome: Hemisection of the cord
Legacy CICMWrecks figure · Source verification pending.
ipsilateral loss of motor functionbelow level of lesiondue to interruption of descending fibres in the lateral corticospinal [pyramidal] tracts.

Initially the paralysis is flaccid, later it becomes hypertonic and hyperreflexic with extensor plantar response [upper motor neurone lesion].
ipsilateral loss of light touch + proprioception + vibrationbelow level of lesiondue to interruption of ascending fibres in the posterior [dorsal] columns
contralateral loss of pain + tempbelow level of lesionInterruption of ascending fibres in the crossed lateral spinothalamic tract
ipsilateral loss of pain + tempat the level of the lesionsegmental anaesthesia of the dermatome

due to damage of the nerve roots and anterior horn cells at this level


Past papers

Exam appearances

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Exam Exact exam wording Candidate success
2008B Q08 Describe the clinical findings you would expect to see in a patient who underwent acute hemi-section of the spinal cord at the upper thoracic level. —