Parsonage-Turner syndrome is the term used to describe a neuritis involving the brachial plexus. It may present with symptoms of an isolated peripheral nerve lesion, although the pathology is thought to lie more proximally. A case describing an isolated anterior interosseus nerve palsy due to an acute brachial neuritis is presented where the electromyographic findings confirmed the diagnosis, but also demonstrated the coexistence of a dual pathology in the form of a cervical radiculopathy. The literature is reviewed regarding etiology, treatment, and prognosis.