Neurologic manifestations of compressive radiculopathy of the first thoracic root

Neurologic deficits in the first thoracic (T1) root distribution are uncomm on and not easily defined. Myotomal charts indicate that distal arm and han d muscles receive significant contributions from both the C8 and T1 roots. A patient with focal T1 radiculopathy is presented who demonstrated motor a xon loss isolated to the abductor pollicis brevis muscle. This finding prov ides another source of evidence that the abductor pollicis brevis is the pr imary T1 motor structure in the upper extremity, improving precision in cli nical and electromyographic diagnosis.