Morphological study of the vasa nervorum in the peripheral branch of human facial nerve.

Given the length of axons reaching to distal regions, all peripheral nerves must derive nutrient supply not only for the nerve cell body, but also for the peripheral parts. Along the course of a peripheral nerve, in general, nutrient vessels accompany nerve fibers to peripheral regions in the form of "vasa nervorum" derived from the epineurium, reaching the endoneurium through the perineurium and forming a capillary plexus. In addition, in reconstructive procedures in plastic surgery, anastomosis of not only nerves, but also the vasa nervorum, has been reported to achieve improved outcomes. The present study therefore observed morphological features of the blood supply to the distal portion of the facial nerve in 14 sides of 14 adult cadavers (age at death, 46-86 years) under stereo microscopy after dye injection. The region of the epineurium was also observed under scanning electron microscopy (SEM). The vasa nervorum was seen to derive from a complex reticulation structure formed mainly by the superficial temporal, facial, transverse facial and zygomatico-orbital arteries with collateral supply from the supraorbital, deep temporal, buccal arteries and parotid branches. SEM showed that one capillary accompanied each perineurium in each nerve fascicle.