The Positions of the Cutaneous Components of the Facial, Glossopharyngeal and Vagal Nerves in the Spinal Tract of V.

Although the debt of the neurosurgeon to the neuroanatomist is virtually incalculable, nowhere is it greater than in the case of surgical interruption of the socalled “pain pathways,” where the results reflect the knowledge of the anatomy. One purpose of the present study was to make medullary trigeminal tractotomy a precise operation for the relief of intractable pain deep in the ear and in the region of the angle of the jaw. Ramon y Cajal (1897) stated that the glossopharyngeal and the vagal nerves transverse the descending tract of V (fig. 1). With customary acumen he suggested that the cutaneous components of these nerves descended in the dorsal one-sixth or one-seventh of the spinal tract of V. However, he was unable to find any terrninations of cutaneous components of the facial nerve. Van Gehuchten (’00) initiated the controversy over the location of the cutaneous components of the glossopharyngeal and the vagal nerves since he was unable to demonstrate any degeneration in the descending tract of V after sectioning these nerves. Kerr (’62), however, has traced, in the cat, descending root fibers of the facial, glossopharyngeal, and vagal nerves to C1 or C2 levels, where they ended in the dorsal horn.