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.

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College Answer

The clinical condition that results from this lesion is the so called Brown-Sequard syndrome.
However only a very small proportion of points were given to mention of the latter, with the
majority of points allocated to knowledge relating to spinal cord anatomy and physiology.
The expected 4 main clinical features that are associated with this lesion are -
1. There is loss of pain and temperature sensation on the contralateral side below the level of
the lesion due to interruption of ascending fibres in the crossed lateral spinothalamic tract.
2. There is loss of vibration, joint position and 2 point discrimination on the ipsilateral side
below the level of the lesion due to interruption of ascending fibres in the posterior [dorsal]
columns.
3. There is paralysis of voluntary movement on the ipsilateral side below the level of the
lesion due 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].
4. Finally there is segmental anaesthesia of the dermatome at the level of the lesion on the
ipsilateral side due to damage of the nerve roots and anterior horn cells at this level.
Some candidates described the clinical features of complete section of the spinal cord which
was not asked for.