COMPARATIVE CHARACTERISTICS OF THE INTRANEURAL STRUCTURE OF THE FACIAL NERVE BEFORE ENTERING AND AFTER EXITING THE EPONYMOUS CANAL
Abstract
The purpose of the study was to investigate the intraneural structure of the facial nerve at its intracranial (cisternal) segment and at the region distal to its exit from the stylomastoid foramen.
Material and methods. The obtained samples were fixed in a solution composed of 2.5% glutaraldehyde, 2% paraformaldehyde, 4% sucrose, and 0.1% picric acid in 0.1 M phosphate buffer (pH = 7.4), and submitted to the Electron Microscopy Laboratory. Initially, the samples were removed from the fixative and rinsed three times (15 minutes each, total 45 minutes) in 0.1 M phosphate buffer (pH = 7.4). According to standard protocols for light and electron microscopy, the post post-fixation stage involved treating the tissue fragments in a mixed solution of 1% OsO ₄ , 0.1 M phosphate buffer, and 1.5% potassium ferricyanide for 1.5 hours.
The results of the study. In the intracranial portion of the facial nerve, the total area of myelinated nerve fibers was 16,290.91 μ m ², corresponding to 77.08% of the total fascicular area. A total of 50,528 myelinated fibers were identified. Among these, fibers with a diameter of 11–4 μ m com- prised 22.52% (11,379 fibers), with a mean diameter of 3.05 ± 0.07 μ m (range: 1.731.73–3.99 μ m); fibers of 44–8 μ m diameter accounted for 41.22% (20,828 fibers), mean diameter: 6.20 ± 0.12 μ m (range: 4.074.07–7.98 μ m); and fibers of 88–12 μ m diameter represented 36.26% (18,321 fibers), mean diameter: 9.11 ± 0.07 μ m (range: 8.018.01–11.55 μ m). After exiting the facial canal, the nerve consisted of multiple fascicles. The number of fascicles was on average 6.0 ± 0.51 on the right side and 6.5 ± 0.53 on the left. Myelinated fibers formed the primary structural component of the facial nerve, occupying 77.3 ± 40.6% of the total cross cross-sectional area on the right side. On the left side, this value was slightly lower. The total number of myelinated fibers was 5,982.5 ± 413.1 on the right and 5,277.3 ± 513.5 on the left.
Conclusion. We assume that there is as much a relationship between the degree of Bell's palsy and the cross cross-sectional diameter of the facial canal as possible. Thus, measuring only the diameter of the facial canal without measuring the diameter of the nerve can be confusing. For this reason, our research aiming to find this relationship will be more accurate.
References
Шадлинский В.Б. Структурный и инфор-мационный анализ некоторых периферических нервов в возрастном отношении / В.Б. Шадлинский, Р.А. Аскеров, А.Дж. Мамедова [и др.] Материалы научной конференции, посв. 100-летию со дня рождения А.С.Гасанова. – Баку: – 2000, – с. 144-145
Kerimzade G, Movsumov N, Shadlinskaya S. Features of Structural Organization of the Human Facial Nerve // Journal of
Islamic International Medical College, – 2024. 4, – р. 267-271. https:// journals.riphah.edu.pk/index.php/jiimc/ article/view/2194
D Amico F. A polychromatic staining method for epoxy embedded tissue: a new combination of methylene blue and basic fuchsine for light microscopy. Biotech Histochem, – 2005. 80(52005. 80(5–6), 6), – p. 207p. 207-210210
Kuo J. Electron microscopy: methods and Kuo J. Electron microscopy: methods and protocols. protocols. - Totowa: Humana Press, Totowa: Humana Press, - 2007, 2007, - 625 p.625 p.
Shin K.J. ThreeShin K.J. Three-dimensional study of the dimensional study of the facial canal using microcomputed facial canal using microcomputed tomography for improved anatomical tomography for improved anatomical comprehension / K.J.Shin, Y.C. Gil, J.Y comprehension / K.J.Shin, Y.C. Gil, J.Y Lee [et al.] // Anat Rec (Hoboken), Lee [et al.] // Anat Rec (Hoboken), – 2014, 2014, 297(10), 297(10), – p. 1808p. 1808-1816 doi: 10.1002/1816 doi: 10.1002/ar.22977.ar.22977.
Li T. Measurement and analysis of facial Li T. Measurement and analysis of facial nerve on fully displayed multislice nerve on fully displayed multislice computed tomographic multiplanar computed tomographic multiplanar reconstruction image / T.Li Z.C.Lai, X.D. reconstruction image / T.Li Z.C.Lai, X.D. Wang [et al.] // J Craniofac Surg. , Wang [et al.] // J Craniofac Surg. , – 2013, 2013, 24(4), 24(4), – p. 1411p. 1411-1413. doi: 10.1097/1413. doi: 10.1097/SCS.0b013e3182903673. SCS.0b013e3182903673.
Talas D.Ü. Morphometric properties of the Talas D.Ü. Morphometric properties of the facial nerve in fetal temporal bones / facial nerve in fetal temporal bones / D.Ü.Talas, O.Beger, T.Koç [et al.] // Int J D.Ü.Talas, O.Beger, T.Koç [et al.] // Int J Pediatr Otorhinolaryngol., Pediatr Otorhinolaryngol., – 2019,116, 2019,116, – p. p. 77-14. doi:10.1016/j.ijporl.2018.10.01214. doi:10.1016/j.ijporl.2018.10.012
Zhang, W. The etiology of Bell's palsy: a Zhang, W. The etiology of Bell's palsy: a review / W.Zhang, L.Xu, T.Luo [et al.] // J review /
Zhang Z. An exploratory study of imaging Zhang Z. An exploratory study of imaging diagnostic clues for overhanging facial diagnostic clues for overhanging facial nerve in ultranerve in ultra-highhigh-resolution CT / resolution CT / Z.R.Zhang, Q.Tang, P.Wu, Zhao [et al.] // Z.R.Zhang, Q.Tang, P.Wu, Zhao [et al.] // Eur Arch Otorhinolaryngol. , Eur Arch Otorhinolaryngol. , – 2023; 2802023; 280(8), (8), – p. 3643p. 3643-3651. doi:10.1007/s004053651. doi:10.1007/s00405-023023-0787907879-00
Rath B, Gidudu JF, Anyoti H. Facial nerve Rath B, Gidudu JF, Anyoti H. Facial nerve palsy including Bell's palsy: Case palsy including Bell's palsy: Case definitions and guidelines for collection, definitions and guidelines for collection, analysis, and presentation of immunisation analysis, and presentation of immunisation safety data. Vaccine., safety data. Vaccine., – 2017;35(15), 2017;35(15), – p. p. 19721972-1983. doi:10.1016/1983. doi:10.1016/j.vaccine.2016.05.023j.vaccine.2016.05.023
Yee G.T. Microanatomy and histological Yee G.T. Microanatomy and histological features of central myelin in the root exit features of central myelin in the root exit zone of facial nerve / G.T.Yee, C.J.Yoo, zone of facial nerve / G.T.Yee, C.J.Yoo, S.R.Han [et al.] // J Korean Neurosurg Soc., S.R.Han [et al.] // J Korean Neurosurg Soc., – 2014,55(5), 2014,55(5), – p. 244p. 244-247. doi: 10.3340/247. doi: 10.3340/jkns.2014.55.5.244.jkns.2014.55.5.244.
Keywords
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Most read articles by the same author(s)
- Kerimzadə G.E., Movsumov N.T., Sultanova M.C., SOME MORPHOMETRIC PARAMETERS OF THE FACIAL CANAL IN MEN AND WOMEN WITH DIFFERENT SKULL SHAPES , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 4 No. 1-2 (2022): JOURNAL OF THEORETICAL CLINICAL AND EXPERIMENTAL MORPHOLOGY
- Aliyeva N. H., Shadlinskaya S. V., STRUCTURAL AND MORPHOMETRIC FEATURES OF LYMPHOID STRUCTURES OF HUMAN INTRAHEPATIC BILE DUCTS IN NORMAL CONDITIONS, WITH CONGENITAL BILIARY ATRESIA AND IN AN EXPERIMENTAL MODEL OF MECHANICAL BILE BLOCKADE IN ANIMALS , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 5 No. 2 (2025): JOURNAL OF THEORETICAL CLINICAL AND EXPERIMENTAL MORPHOLOGY
- Shadlinskaya S.V., Movsumov N.T., Some morphological features of lymphoid apparatus in the uterine tubes women in old age , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 2 No. 3-4 (2019): Journal of Theoretical, Clinical and Experimental Morphology
- Mövsümov N.T., MY PRIDE, ACADEMICIAN VAGIF SHADLINSKİ , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 5 No. 1 (2025): JOURNAL OF THEORETICAL CLINICAL AND EXPERIMENTAL MORPHOLOGY
- Kerimzade G. E., Movsumov N.T., RATIO OF THE DIAMETER OF THE FACIAL NERVE TO THE DIAMETER OF THE SAME CANAL AT THE LEVEL OF THE STYLOMASTOID FORAMEN , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 5 No. 1 (2025): JOURNAL OF THEORETICAL CLINICAL AND EXPERIMENTAL MORPHOLOGY
- Shadlinskaya S. V., Mustafayeva N. A., Alizadeh Z. H., NORMAL VARIANTS OF MORPHOLOGY OF ARTERIES OF THE HUMAN CIRCLE OF WILLIS , Journal of Theoretical, Clinical and Experimental Morphology: Vol. 5 No. 1 (2025): JOURNAL OF THEORETICAL CLINICAL AND EXPERIMENTAL MORPHOLOGY