Dixon A, Sharma R, Gaillard F, et al. Transition zone (nerve). Reference article, Radiopaedia.org (Accessed on 25 Feb 2025) https://doi.org/10.53347/rID-57135
The transition zone of a nerve, also known as the Obersteiner-Redlich zone, describes a region of a few millimeters where the myelin sheath changes from a central to peripheral type as enveloping glial cells are replaced by Schwann cells.
Transition zones are of variable length, not a sudden transition, but rather, the central myelin component extends further in the center of the nerve than on the periphery. The location of the transition zone is also variable distance from the nerve root entry zone, depending on the cranial nerve and differing to a degree between individuals 1,4,5,7-9:
The transition zone is often attributed to being the site of origin of vestibular schwannomas, however this has been shown to be an erroneous myth across multiple studies 2,3,6.
History and etymology
The zone is eponymously attributed to Emil Redlich (1866-1930) and Heinrich Obersteiner (1847-1922), Austrian physicians.
1. Haller S, Etienne L, Ko vari E, Varoquaux A, Urbach H, Becker M. Imaging of Neurovascular Compression Syndromes: Trigeminal Neuralgia, Hemifacial Spasm, Vestibular Paroxysmia, and Glossopharyngeal Neuralgia. AJNR Am J Neuroradiol. 2016;37(8):1384-92. doi:10.3174/ajnr.a4683 - Pubmed
2. Roosli C, Linthicum, Jr. F, Cureoglu S, Merchant S. What Is the Site of Origin of Cochleovestibular Schwannomas? Audiology and Neurotology. 2012;17(2):121-5. doi:10.1159/000331394 - Pubmed
3. Xenellis J & Linthicum F. On the Myth of the Glial/schwann Junction (Obersteiner-Redlich Zone): Origin of Vestibular Nerve Schwannomas. Otol Neurotol. 2003;24(1):1. doi:10.1097/00129492-200301000-00001 - Pubmed
4. Guclu B, Sindou M, Meyronet D, Streichenberger N, Simon E, Mertens P. Anatomical Study of the Central Myelin Portion and Transitional Zone of the Vestibulocochlear Nerve. Acta Neurochir. 2012;154(12):2277-83. doi:10.1007/s00701-012-1479-x - Pubmed
5. Guclu B, Sindou M, Meyronet D, Streichenberger N, Simon E, Mertens P. Cranial Nerve Vascular Compression Syndromes of the Trigeminal, Facial and Vago-Glossopharyngeal Nerves: Comparative Anatomical Study of the Central Myelin Portion and Transitional Zone; Correlations with Incidences of Corresponding Hyperactive Dysfunctional Syndromes. Acta Neurochir. 2011;153(12):2365-75. doi:10.1007/s00701-011-1168-1 - Pubmed
6. Constanzo F, Teixeira B, Sens P, Escuissato D, Ramina R. Cerebellopontine Angle Schwannomas Arising from the Intermediate Nerve: A Scoping Review. Neurosurg Rev. 2019;43(6):1431-41. doi:10.1007/s10143-019-01173-6 - Pubmed
8. Fraher J, Smiddy P, O'Sullivan V. The Central-Peripheral Transitional Regions of Cranial Nerves. Oculomotor Nerve. J Anat. 1988;161:103-13. PMC1262094 - Pubmed
9. Quanchareonsap W, Jariyakosol S, Apinyawasisuk S, Roumwong A, Chentanez V. Microanatomy of the Central Myelin Portion and Transitional Zone of the Oculomotor and Abducens Nerves. Folia Morphol (Warsz). 2023;82(3):543-50. doi:10.5603/FM.a2022.0057 - Pubmed