Teaching neuroimages: swollen T1 nerve root in neurogenic thoracic outlet syndrome.

A 17-year-old girl without any history of considerable trauma or previous disease was admitted with weakness and wasting in the right forearm and hand, more marked on the thenar eminence (figure). EMG revealed unrecordable medial antebrachial cutaneous sensory and low-amplitude median motor responses (recorded from thenar muscles) along with chronic neurogenic changes in the hand muscles. MRI showed a fusiform focal expansion of the right T1 root (figure). Neurogenic thoracic outlet syndrome (NTOS) was diagnosed and surgically decompressed.