Muscle hypertrophy secondary to the tethered cord syndrome.

Segmental muscle enlargement occurs in a variety of neurogenic conditions. We present a case with calf hypertrophy, likely produced by partial denervation and continuous neuromuscular irritability, which was caused by a tethered spinal cord that was demonstrated by MRI. Muscle MRI correlated with muscle biopsy findings in which atrophy and hypertrophy were accompanied by rimmed vacuoles.