Fetal facial nerve course in the ear region revisited

Zhe Wu Jin, Kwang Ho Cho, Hiroshi Abe, Yukio Katori, Gen Murakami, Jose Francisco Rodríguez-Vázquez

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Purpose: The aim of this study was to re-examine the structures that determine course of the facial nerve (FN) in the fetal ear region. Materials and methods: We used sagittal or horizontal sections of 28 human fetuses at 7–8, 12–16, and 25–37 weeks. Results: The FN and the chorda tympani nerve ran almost parallel until 7 weeks. The greater petrosal nerve (GPN) ran vertical to the distal FN course due to the trigeminal nerve ganglion being medial to the geniculate ganglion at 7 weeks. Afterwards, due to the radical growth of the former ganglion, the GPN became an anterior continuation of the FN. The lesser petrosal nerve ran straight, parallel to the FN at 7 weeks, but later, it started to wind along the otic capsule, possibly due to the upward invasion of the tympanic cavity epithelium. Notably, the chorda tympanic nerve origin from the FN, and the crossing between the vagus nerve branch and the FN, was located outside of the temporal bone even at 37 weeks. The second knee of the FN was not evident, in contrast to the acute anterior turn below the chorda tympanic nerve origin. In all examined fetuses, the apex of the cochlea did not face the middle cranial fossa, but the tympanic cavity. Conclusion: Topographical relation among the FN and related nerves in the ear region seemed not to be established in the fetal age but after birth depending on growth of the cranial fossa.

Original languageEnglish
Pages (from-to)885-895
Number of pages11
JournalSurgical and Radiologic Anatomy
Volume39
Issue number8
DOIs
Publication statusPublished - 2017 Aug 1

Keywords

  • Auricular branch of the vagus nerve
  • Chorda tympani nerve
  • Facial nerve
  • Genu
  • Greater petrosal nerve
  • Human fetus
  • Topographical anatomy

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine
  • Radiology Nuclear Medicine and imaging

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  • Cite this

    Jin, Z. W., Cho, K. H., Abe, H., Katori, Y., Murakami, G., & Rodríguez-Vázquez, J. F. (2017). Fetal facial nerve course in the ear region revisited. Surgical and Radiologic Anatomy, 39(8), 885-895. https://doi.org/10.1007/s00276-017-1818-y