The structural basis of Felice Fontana's spiral bands and their relationship to nerve injury.

In 1779, Felice Fontana, using a six-power hand-held magnifying lens, described what appeared to be spiral bands surrounding the peripheral nerve. He hypothesized that these bands were due to an optical illusion related to the underlying undulations of the individual nerve fibers, which he was the first to observe with an early microscope. The present study examines the historical basis of Fontana's work, confirms with intrafascicular dissection that the bands are an illusion created by unstretched nerve fibers, and relates their clinical disappearance to current concepts of the pathophysiology of chronic nerve compression and nerve injury.