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Rotenstreich L, Eran A, Siegler Y, Grossman R, Edery N, Cohen R, Marom A. Unveiling the vulnerability of the human abducens nerve: insights from comparative cranial base anatomy in mammals and primates. Front Neuroanat 2024; 18:1383126. [PMID: 38741761 PMCID: PMC11089250 DOI: 10.3389/fnana.2024.1383126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 04/11/2024] [Indexed: 05/16/2024] Open
Abstract
The topographic anatomy of the abducens nerve has been the subject of research for more than 150 years. Although its vulnerability was initially attributed to its length, this hypothesis has largely lost prominence. Instead, attention has shifted toward its intricate anatomical relations along the cranial base. Contrary to the extensive anatomical and neurosurgical literature on abducens nerve anatomy in humans, its complex anatomy in other species has received less emphasis. The main question addressed here is why the human abducens nerve is predisposed to injury. Specifically, we aim to perform a comparative analysis of the basicranial pathway of the abducens nerve in mammals and primates. Our hypothesis links its vulnerability to cranial base flexion, particularly around the sphenooccipital synchondrosis. We examined the abducens nerve pathway in various mammals, including primates, humans (N = 40; 60% males; 40% females), and human fetuses (N = 5; 60% males; 40% females). The findings are presented at both the macroscopic and histological levels. To associate our findings with basicranial flexion, we measured the cranial base angles in the species included in this study and compared them to data in the available literature. Our findings show that the primitive state of the abducens nerve pathway follows a nearly flat (unflexed) cranial base from the pontomedullary sulcus to the superior orbital fissure. Only the gulfar segment, where the nerve passes through Dorello's canal, demonstrates some degree of variation. We present evidence indicating that the derived state of the abducens pathway, which is most pronounced in humans from an early stage of development, is characterized by following the significantly more flexed basicranium. Overall, the present study elucidates the evolutionary basis for the vulnerability of the abducens nerve, especially within its gulfar and cavernous segments, which are situated at the main synchondroses between the anterior, middle, and posterior cranial fossae-a unique anatomical relation exclusive to the abducens nerve. The principal differences between the pathways of this nerve and those of other cranial nerves are discussed. The findings suggest that the highly flexed human cranial base plays a pivotal role in the intricate anatomical relations and resulting vulnerability of the abducens nerve.
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Affiliation(s)
- Liat Rotenstreich
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
| | - Ayelet Eran
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
- Neuroradiology Unit, Department of Radiology, Rambam Medical Center, Haifa, Israel
| | - Yoav Siegler
- Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel
| | - Rachel Grossman
- Department of Neurosurgery, Rambam Medical Center, Haifa, Israel
| | - Nir Edery
- Department of Pathology, Kimron Veterinary Institute, Bet Dagan, Israel
| | - Roni Cohen
- Edmond and Lily Safra Center for Brain Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Assaf Marom
- Laboratory for Anatomy and Human Evolution, The Farkas Family Center for Anatomical Research and Education, Rappaport Faculty of Medicine, Department of Neuroscience, Technion – Israel Institute of Technology, Haifa, Israel
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Tiefenbach J, Demetriades AK. Revisiting Galen: enduring contributions from ancient times towards modern neurosurgery. J Neurosurg Sci 2024; 68:232-237. [PMID: 35766212 DOI: 10.23736/s0390-5616.22.05821-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2024]
Abstract
This historical vignette aims to reflect on the life of Claudius Galen and critically discuss his contributions towards modern neurosurgical practice; specifically, neuroanatomy, neurophysiology, and cranial trepanation. Born in 129 AD in the Greek city of Pergamon, Galen dedicated his early life to the study of medicine and established himself as one of the foremost physicians of the time. Through vivisections of Barbary apes, he was one of the first to provide a detailed description of cranial nerves, the ventricular system of the brain, and various deep brain structures. He made an important distinction between motor and sensory nerves and mapped out the fundamental arrangement of neuronal fibers within the spinal cord. However, his fundamental understanding of neurophysiology, as well as cerebral blood circulation, was largely flawed as it was based on speculation of inter-species comparative anatomy. On the technical side, he made a modest contribution to the practice of cranial trepanation and his writings helped establish the technique as an essential component of a surgeon's armamentarium. His work in the fields relevant to modern neurosurgery, although imperfect with the benefit of hindsight, laid the important foundation for much of the progress of neurosurgical practice in the Renaissance and beyond.
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Affiliation(s)
- Jakov Tiefenbach
- Neurological Institute, Cleveland Clinic Foundation, Cleveland, OH, USA -
- Department of Neurosurgery, Royal Infirmary of Edinburgh, Edinburgh, UK -
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López-Ojeda W, Hurley RA. Cranial Nerve Zero (CN 0): Multiple Names and Often Discounted yet Clinically Significant. J Neuropsychiatry Clin Neurosci 2022; 34:A4-99. [PMID: 35491548 DOI: 10.1176/appi.neuropsych.22010021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Wilfredo López-Ojeda
- Veterans Affairs Mid-Atlantic Mental Illness Research, Education, and Clinical Center and Research and Academic Affairs Service Line, W.G. Hefner Veterans Affairs Medical Center, Salisbury, N.C. (López-Ojeda, Hurley); Departments of Psychiatry and Behavioral Medicine (López-Ojeda, Hurley) and Radiology (Hurley), Wake Forest School of Medicine, Winston-Salem, N.C.; Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston (Hurley)
| | - Robin A Hurley
- Veterans Affairs Mid-Atlantic Mental Illness Research, Education, and Clinical Center and Research and Academic Affairs Service Line, W.G. Hefner Veterans Affairs Medical Center, Salisbury, N.C. (López-Ojeda, Hurley); Departments of Psychiatry and Behavioral Medicine (López-Ojeda, Hurley) and Radiology (Hurley), Wake Forest School of Medicine, Winston-Salem, N.C.; Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston (Hurley)
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Wijdicks EFM. Historical awareness of the brainstem: From a subsidiary structure to a vital center. Neurology 2020; 95:484-488. [PMID: 32934155 DOI: 10.1212/wnl.0000000000010504] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 07/15/2020] [Indexed: 11/15/2022] Open
Abstract
The historical trajectory of the discovery of the brainstem as a vital center has been rarely explored. Focusing on its tracts and neurons first, anatomists much later expanded their understanding of the brainstem with the discovery of groups of nuclear networks that affected major vital functions. Comparative anatomists (i.e., Edinger) postulated a primordial paleopallium that indirectly implied the centrality of the brainstem and a neopallidum with its differentiation and specialization up to Homo sapiens Methods that governed the discovery of the brainstem were (1) comparative anatomy, (2) embryonic growth, (3) vivisection, (4) brain dissection, and, much later, (5) microscopy and chemical feedback loops. This historical study traces how neuroscientists of the 18th and 19th century became increasingly aware of the vital functions performed by the brainstem. The anatomists of the 20th century found the ascending reticular formation, the respiratory center, and pressor centers-all automatic and vital functions. It took centuries for this realization to open the way to use the testable brainstem centers to establish the criteria for a neurologic determination of death. The ontogenetic conclusion is that the brainstem is the ancestor of the developed human brain; the physiologic conclusion is that the brainstem is a vital center and a structural support system and conduit. When afunctional, life ends.
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Affiliation(s)
- Eelco F M Wijdicks
- From the Mayo Clinic Division of Neurocritical Care and Hospital Neurology.
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Martínez-Marcos A, Sañudo JR. Cranial Nerves: Morphology and Clinical Relevance. Anat Rec (Hoboken) 2020; 302:555-557. [PMID: 30810281 DOI: 10.1002/ar.24106] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 02/24/2019] [Indexed: 01/13/2023]
Abstract
This Special Issue entitled "Cranial Nerves: phylogeny, ontogeny, morphology and clinical significance" has been divided into two consecutive volumes. This second volume is devoted to morphology and clinical relevance. Articles in this volume examine these topics from a macroscopic point of view and with a surgical interest. This volume includes articles on oculomotor nerves III, IV, and VI and their course in the orbit; intracranial and extracranial views of the V and VII pairs; and branching patterns of IX, X, XI, and XII pairs with medical significance. Together, these articles provide a general overview of cranial nerves' gross anatomical organization, as well as improving on the knowledge necessary for clinical approaches. Anat Rec, 302:555-557, 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Alino Martínez-Marcos
- Laboratorio de Neuroplasticidad y Neurodegeneración, Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, 13071, Ciudad Real, Spain
| | - José Ramón Sañudo
- Departamento de Anatomía y Embriología, Facultad de Medicina, Universidad Complutense de Madrid, 28040, Madrid, Spain
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Trejo JL. Cranial Nerves: Mind Your Head. Anat Rec (Hoboken) 2019; 302:374-377. [DOI: 10.1002/ar.24071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/20/2018] [Accepted: 01/28/2019] [Indexed: 12/20/2022]
Affiliation(s)
- José Luis Trejo
- Department of Translational Neuroscience, CSIC; Cajal Institute; Madrid Spain
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Laitman JT, Albertine KH. The Anatomical Record Shows its Nerve (S): An Exploration of New Findings in our Special Issue on the Cranial Nerves. Anat Rec (Hoboken) 2019; 302:371-373. [PMID: 30663247 DOI: 10.1002/ar.24070] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/14/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Jeffrey T Laitman
- Center for Anatomy and Functional Morphology, Senior Associate Editor of The Anatomical Record, Mount Sinai School of Medicine, New York, New York
| | - Kurt H Albertine
- Department of Pediatrics, Editor-in-Chief, The Anatomical Record, University of Utah School of Medicine, Salt Lake City, Utah
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