title: Sex differences in morphometric aspects of the peripheral nerves and related diseases.
abstract: BACKGROUND
  The elucidation of the relationship between the morphology of the peripheral nerves and the diseases would be valuable in developing new medical treatments on the assumption that characteristics of the peripheral nerves in females are different from those in males.
  
  
  METHODS
  We used 13 kinds of the peripheral nerve. The materials were obtained from 10 Japanese female and male cadavers. We performed a morphometric analysis of nerve fibers. We estimated the total number of myelinated axons, and calculated the average transverse area and average circularity ratio of myelinated axons in the peripheral nerves.
  
  
  RESULTS
  There was no statistically significant difference in the total number, average transverse area, or average circularity ratio of myelinated axons between the female and male specimens except for the total number of myelinated axons in the vestibular nerve and the average circularity ratio of myelinated axons in the vagus nerve.
  
  
  CONCLUSIONS
  The lower number of myelinated axons in the female vestibular nerve may be one of the reasons why vestibular disorders have a female preponderance. Moreover, the higher average circularity ratio of myelinated axons in the male vagus nerve may be one reason why vagus nerve activity to modulate pain has a male preponderance.
authors: Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
authors: Hiroshi
authors: H
authors: Moriyama
authors: Department of Anatomy, Tokyo Medical University, Tokyo, Japan.
authors: Shogo
authors: S
authors: Hayashi
authors: Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
authors: Yuriko
authors: Y
authors: Inoue
authors: Department of Anatomy, Tokyo Medical University, Tokyo, Japan.
authors: Masahiro
authors: M
authors: Itoh
authors: Department of Anatomy, Showa University School of Medicine, Tokyo, Japan.
authors: Naruhito
authors: N
authors: Otsuka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001369:Axons / Q000648:ultrastructure; D002102:Cadaver; D002452:Cell Count; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000648:ultrastructure; D009412:Nerve Fibers / Q000648:ultrastructure; D010525:Peripheral Nerves / Q000033:anatomy & histology* / Q000473:pathology*; D010523:Peripheral Nervous System Diseases / Q000473:pathology*; D012727:Sex Characteristics; D015837:Vestibular Diseases / Q000473:pathology; D014725:Vestibular Nerve / Q000473:pathology / Q000648:ultrastructure
keywords: Peripheral nerve; axon; human; morphometry; neurological disorder; sex difference