Morphological evaluation of median nerve: why ultrasound?

A 45-year-old man came to our attention after a cut trauma at left wrist level, occurred 2 months before. The patient complained of paresthesia in median nerve territory and strength deficit at thenar muscles. The subject presented a palpable formation at the trauma level. Electrophysiology showed sensory-motor axonal impairment of the nerve. US examination was performed using a 18 MHz probe