Rucksack-induced plexopathy mimicking a lateral antebrachial cutaneous neuropathy

A 20-yr-old active duty soldier complained of right lateral forearm numbness that began shortly after carrying 100 lbs of equipment (20-lb load-bearing equipment, 20-lb individual body armor, and 60-lb rucksack) while deployed during Operation Iraqi Freedom. Physical examination revealed normal strength but decreased sensation over the right lateral forearm, thumb, and index finger. Imaging studies were normal. Electrodiagnostic studies revealed an absent right lateral antebrachial cutaneous nerve conduction study with abnormal electromyography findings in the right deltoid and biceps brachii. He was diagnosed with an upper trunk brachial plexopathy. The patient's symptoms gradually resolved with conservative treatment. Although rucksack palsies have been previously reported, this relatively rare cause of brachial plexus injury has been generally declining with the reengineering of more ergonomically favorable rucksacks. It is possible that the additional body armor may have contributed.