Myelography in the diagnosis and prognosis of brachial plexus injuries.

Diagram of a transverse section of the neck at the level of C.6, to demonstrate the origin and the course of the posterior branches of the spinal nerves. On the right side is shown intraforaminal avulsion of the spinal root. The electromyograph of the deep posterior neck muscles will show fibrillation potentials: an unfavourable prognosis. On the left side is shown extraforaminal damage of the brachial plexus. The electromyograph of the deep posterior neck muscles will be normal: a favourable prognosis.