Three patients suffered injury to the upper trunk of the right brachial plexus from firearm recoil. The proposed mechanism is entrapment of the upper trunk of the plexus between the forcefully retracting clavicle and the underlying scalene muscles. Two patients had only temporary disability, but the third continued shooting and his deficit is permanent.
Wanamaker WM. Firearm Recoil Palsy. Arch Neurol. 1974;31(3):208–209. doi:10.1001/archneur.1974.00490390090012