The surgical anatomy of the fifth lumbar spinal nerve root.

Irritation, compression or tension of the 5th lumbar nerve root is a major cause of back pain. A sound knowledge of the anatomy of this nerve is necessary to understand the role it plays in the production of back pain. The anatomy of the 5th lumbar nerve root is reviewed, and demonstrated with dissections of 5 cadaveric spines. The possible anatomical sites of irritation, compression or tension of the 5th lumbar nerve root are listed and briefly discussed.