Brachial plexus injury as a consequence of carrying a heavy backpack frequently described in military population 
Seen also in boy scouts, hikers, mountaineering 
Also described secondary to wearing body armor 
Known by a variety of names: pack palsy, backpack palsy,<unk> , trekker's palsy, Pallbearer's palsy
Decreased because of more ergonomically designed packs
Rucksack paralysis
Parsonage-Turner syndrome
Tick paralysis
Toxic neuropathy
Meralgia paresthetica
Progressive neuropathy secondary to exposure 
Horner syndrome
See weakness, numbness