The brachial plexus lies in the posterior triangle of the neck between the scalenus anterior and scalenus medius muscles. At the root of the neck, it lies behind the clavicle.
The most common injury is severe traction with the arm in abduction e.g. after a motor cycle accident. Partial paralysis may also result from shoulder dislocation. Direct injury to the brachial plexus can result from a stab or gunshot wound.
Last reviewed 01/2018