foot drop

Last reviewed 09/2023

Foot drop is a common and distressing problem where there is a weakness of the dorsiflexion muscles in the foot resulting in difficulty in walking and an increased risk of falling (1,2)

The most common cause of foot drop is peroneal neuropathy.

  • less often it may be due to  L5 radiculopathy or polyneuropathy and much less often by sciatic neuropathies, lumbar plexopathies, mononeuritis multiplex, or myopathies. 
  • rarely it can be due to central causes (such as cerebral ischaemia), anterior horn cell diseases, cauda equina compression, and muscle dystrophy - usually these produce other symptoms (1,2)

If a patient has a foot drop, then a clinical indicator to the underlying pathology can be achieved by testing the ankle jerk. If the ankle jerk is absent then an L5 lesion is likely. A normal ankle jerk indicates a possible common peroneal palsy. The ankle jerk will be increased in an upper motor neurone lesion.

Notes:

  • bilateral foot-drop has been reported as a possible presentation of diabetes mellitus (1)

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