Distal Leg Weakness

Plantar flexion and/or extension weakness is usually neuromuscular in nature. Rarely, focal foot dystonia, ankle arthritis, and spasticity lead to diagnostic confusion. Painful sequential foot drop is a common feature of vasculitis. Preserved EDB bulk in the face of foot drop is a feature of myopathy. Progressive painless weakness of the foot flexion and extension with normal sensation and brisk deep tendon reflexes are typically seen in ALS. In patients with chronic bilateral foot drop, examination of the scapulae is essential to rule out scapuloperoneal syndrome and FSHD. In inflammatory neuropathies, distal leg weakness is the last to respond to therapy and some residual deficit is common.