06/12/2025
Fasciculations (Tongue and Lower Limb)
A 73-year-old man with amyotrophic lateral sclerosis. Fasciculations are involuntary, repetitive, irregular, and visible contractions of muscle fibers secondary to spontaneous discharge of the motor unit (anterior horn cell or axon).
Isolated fasciculations without other neurologic findings can occur in healthy individuals. However, fasciculations when accompanied by atrophy or weakness indicate a lesion in the lower motor neuron.
Segment 1 – Tongue fasciculations. Bilateral tongue fasciculations and wasting are noted. Tongue fasciculations are typically best appreciated by observing the tongue while it is resting on the floor of the mouth.
Segment 2 – Lower limb fasciculations. Spontaneous bilateral proximal leg fasciculations are seen and can be further provoked by gently tapping the affect muscle group. Atrophy of the quadriceps muscles (more severe in the left leg) is also noted. The presence bilateral tongue and limb fasciculations with progressive weakness and upper motor neuron signs in the absence of sensory complaints should raise suspicion of possible amyotrophic lateral sclerosis.
