Paraplegia in Extension and Flexion

Paraplegia in extension and paraplegia in flexion occur only after the spinal shock has ceased. Paraplegia in extension indicates an increase in the extensor muscle tone owing to the overactivity of gamma efferent nerve fibers to muscle spindles as the result of the release of these neurons from the higher centers. Also, extrapyramidal descending tracts (vestibulospinal and rubrospinal tracts) may escape injury in incomplete spinal cord injury leading to increased activity in extensor motor neurons.

Paraplegia in extension may convert to paraplegia in flexion if the damage to the spinal cord increases, leading to destruction of the above mentioned extrapyramidal tracts. Paraplegia in flexion may be associated with mass reflex where there is spontaneous urination, defecation and sweating on scratching the skin over the medial side of the thigh.

Rawlings, Leo, Public domain, via Wikimedia Commons
Paraplegia in ExtensionParaplegia in Flexion
CausePyramidal lesionPyramidal and Extrapyramidal lesion
HypertoniaMore in extensor group of musclesMore in flexor group of muscles
Position of lower limbsExtended (hip & knee extended, feet plantarflexed)Flexed (hip & knee flexed, feet dorsiflexed)
Deep reflexesExaggeratedLess exaggerated
Mass reflexAbsentMay be present
BladderPrecipitancyAutomatic bladder


  1. Clinical Neuroanatomy By Richard S. Snell
  2. Short Cases in Clinical Medicine By A B M Abdullah

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