Bilateral aplasia of the tibialis anterior and unilateral aplasia of the extensor hallucis longus muscles.

A 35-year-old woman presented with bilateral leg pain on walking that had been present since childhood. Clinical examination showed bilateral absence of the tibialis anterior tendons and the left extensor hallucis longus tendon. Magnetic resonance imaging revealed that signal intensities in the location of the tibialis anterior muscles bilaterally and the left extensor hallucis longus muscle were uniformly high on T1-weighted images, consistent with fat tissue and aplastic muscles: findings not previously reported.