{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T19:34:59Z","timestamp":1786649699496,"version":"build-2736575974"},"reference-count":17,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"2","license":[{"start":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T00:00:00Z","timestamp":1741132800000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-sa\/4.0"}],"content-domain":{"domain":["lww.com","ovid.com"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2025,4]]},"abstract":"<jats:sec>\n                    <jats:title>Background:<\/jats:title>\n                    <jats:p>Atlanto-occipital and atlantoaxial assimilation are rare congenital abnormalities characterized by abnormal fusion of the atlas vertebra with the occipital bone or the axis vertebra, respectively, within the craniovertebral junction. These anomalies can significantly alter the biomechanics and structural integrity of the cervical spine, leading to diverse clinical presentations ranging from restricted neck mobility to neurological deficits. Accordingly, this study aims to investigate the prevalence, anatomical abnormalities, and clinical significance of atlanto-occipital and atlantoaxial assimilation in the Asian population.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Materials and Methods:<\/jats:title>\n                    <jats:p>A total of 82 human dry skulls and 82 sets of dry cervical vertebrae were examined for the presence of atlanto-occipital and atlantoaxial assimilation. Detailed morphometric analysis was performed to document the fusion patterns and variations in anatomical structures. The data were analyzed to determine the prevalence of these congenital anomalies and their implications for craniovertebral stability and neurological function.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results:<\/jats:title>\n                    <jats:p>Among the 82 skulls and 82 cervical vertebrae examined, atlanto-occipital assimilation was identified in 3 skulls (3.65%), whereas atlantoaxial assimilation was observed in 2 cases (2.43%). Combined occurrences of both anomalies were found in 2 skulls (2.43%) of the sample.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion:<\/jats:title>\n                    <jats:p>A thorough understanding of atlanto-occipital and atlantoaxial assimilation is clinically crucial due to its potential impact on the structural and functional dynamics of the craniovertebral junction. These congenital anomalies, though infrequent, can pose considerable clinical challenges, including compromised craniovertebral stability and an increased risk of neurological symptoms. Early diagnosis and careful clinical evaluation are crucial for managing potential complications associated with these conditions.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.4103\/aam.aam_291_24","type":"journal-article","created":{"date-parts":[[2025,3,5]],"date-time":"2025-03-05T11:03:38Z","timestamp":1741172618000},"page":"415-420","update-policy":"https:\/\/doi.org\/10.1097\/lww.0000000000001000","source":"Crossref","is-referenced-by-count":3,"title":["Anatomical Study and Clinical Significance of Atlanto-occipital and Atlantoaxial Assimilation Anomaly in Asian Population"],"prefix":"10.4103","volume":"24","author":[{"given":"Kosuri Kalyan","family":"Chakravarthi","sequence":"first","affiliation":[{"name":"Department of Anatomy, Manipal University College Malaysia, Melaka, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Venumadhav","family":"Nelluri","sequence":"additional","affiliation":[{"name":"Department of Anatomy, Manipal University College Malaysia, Melaka, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Raju","family":"Sugavasi","sequence":"additional","affiliation":[{"name":"Department of Anatomy, Manipal University College Malaysia, Melaka, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Deepthynadh","family":"Reghunadhan","sequence":"additional","affiliation":[{"name":"Department of Anatomy, Manipal University College Malaysia, Melaka, Malaysia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","published-online":{"date-parts":[[2025,3,5]]},"reference":[{"key":"R1-20260423","first-page":"32","article-title":"Atlas assimilation: A case report","volume":"6","author":"Ranade","year":"2007","journal-title":"Neuroanatomy"},{"key":"R2-20260423","first-page":"73","article-title":"Occipitalization of atlas: A case report","volume":"2","author":"Saheb","year":"2010","journal-title":"J Biomed Sci Res"},{"key":"R3-20260423","doi-asserted-by":"crossref","first-page":"108592.","DOI":"10.1016\/j.ijscr.2023.108592","article-title":"Partial atlantooccipital assimilation causing atlantoaxial instability and early myelopathy in an adult treated with occipitocervical fusion: A case report","volume":"109","author":"Pathinathan","year":"2023","journal-title":"Int J Surg Case Rep"},{"key":"R4-20260423","doi-asserted-by":"crossref","first-page":"176","DOI":"10.2319\/091306-370.1","article-title":"Cervical vertebrae anomalies-incidental findings on lateral cephalograms","volume":"78","author":"Soni","year":"2008","journal-title":"Angle Orthod"},{"key":"R5-20260423","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1007\/s00276-016-1687-9","article-title":"A morphometric study of the atlas occipitalization and coexisted congenital anomalies of the vertebrae and posterior cranial fossa with neurological importance","volume":"39","author":"Natsis","year":"2017","journal-title":"Surg Radiol Anat"},{"key":"R6-20260423","doi-asserted-by":"crossref","first-page":"34","DOI":"10.5005\/jp-journals-10055-0007","article-title":"Occipitalization of atlas: A case report with its ontogenic basis and review of literature","volume":"1","author":"Piplani","year":"2017","journal-title":"AMEI\u2019s Curr Trends Diagn Treat"},{"key":"R7-20260423","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1111\/j.1447-073X.2006.00129.x","article-title":"Total occipitalization of the atlas","volume":"81","author":"Al-Motabagani","year":"2006","journal-title":"Anat Sci Int"},{"key":"R8-20260423","doi-asserted-by":"crossref","first-page":"528","DOI":"10.3340\/jkns.2015.58.6.528","article-title":"Anatomical variant of atlas: Arcuate foramen, occpitalization of atlas, and defect of posterior arch of atlas","volume":"58","author":"Kim","year":"2015","journal-title":"J Korean Neurosurg Soc"},{"key":"R9-20260423","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1007\/s00586-010-1303-3","article-title":"Occipitocervical fusion","volume":"19","author":"Abumi","year":"2010","journal-title":"Eur Spine J"},{"key":"R10-20260423","doi-asserted-by":"crossref","first-page":"1109","DOI":"10.1007\/s00381-008-0600-1","article-title":"Craniocervical developmental anatomy and its implications","volume":"24","author":"Menezes","year":"2008","journal-title":"Childs Nerv Syst"},{"key":"R11-20260423","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1097\/00007632-197901000-00002","article-title":"Congenital atlantoaxial fusion. A case report","volume":"4","author":"Gunderson","year":"1979","journal-title":"Spine (Phila Pa 1976)"},{"key":"R12-20260423","first-page":"287","article-title":"Possible compression of the atlantal segment of the vertebral artery in occipitalisation","volume":"70","author":"Skrzat","year":"2011","journal-title":"Folia Morphol (Warsz)"},{"key":"R13-20260423","doi-asserted-by":"crossref","first-page":"641","DOI":"10.4103\/aam.aam_73_24","article-title":"Anatomical and radiological findings of abnormal calcified structures within and around the foramen transversarium and its clinical implications","volume":"23","author":"Chakravarthi","year":"2024","journal-title":"Ann Afr Med"},{"key":"R14-20260423","first-page":"501","article-title":"Osseous anomalies of the craniovertebral junction","volume":"85","author":"Hensinger","year":"1988","journal-title":"Spine"},{"key":"R15-20260423","doi-asserted-by":"crossref","first-page":"354","DOI":"10.1002\/1098-2353(2000)13:5<354::AID-CA5>3.0.CO;2-6","article-title":"Bony observations of some morphological variations and anomalies of the craniovertebral region","volume":"13","author":"Taitz","year":"2000","journal-title":"Clin Anat"},{"key":"R16-20260423","doi-asserted-by":"crossref","first-page":"189","DOI":"10.14245\/kjs.2013.10.3.189","article-title":"Cervical myelopathy secondary to atlanto-occipital assimilation: The usefulness of the simple decompressive surgery","volume":"10","author":"Kim","year":"2013","journal-title":"Korean J Spine"},{"key":"R17-20260423","doi-asserted-by":"crossref","first-page":"291","DOI":"10.1227\/NEU.0b013e3182011262","article-title":"The craniovertebral junction area and the role of the ligaments and membranes","volume":"68","author":"Debernardi","year":"2011","journal-title":"Neurosurgery"}],"container-title":["Annals of African Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.ovid.com\/10.4103\/aam.aam_291_24","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T18:57:18Z","timestamp":1786647438000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.ovid.com\/10.4103\/aam.aam_291_24"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,5]]},"references-count":17,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2025]]}},"URL":"https:\/\/doi.org\/10.4103\/aam.aam_291_24","relation":{},"ISSN":["1596-3519","0975-5764"],"issn-type":[{"value":"1596-3519","type":"print"},{"value":"0975-5764","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,3,5]]},"assertion":[{"value":"2024-12-23","name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2024-12-26","name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}}]}}