Neural blockade for upper-extremity pain.

Carefully performed and interpreted neural blockade can be a useful adjunct in both the diagnosis and treatment of painful syndromes of the upper extremity. Pain is a very difficult entity to quantify and diagnose specifically because of its subjective nature, vast differences between patients and their response to pain, and largely because of our inexact understanding of its physiology. Best results of block therapy require thorough understanding of these complexities and limitations, and a rational, careful examination of the data it provides.