open access

Vol 69, No 3 (2010)
ORIGINAL ARTICLES
Published online: 2010-08-02
Submitted: 2012-02-06
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Geometry of the articular facets of the lateral atlanto-axial joints in the case of occipitalization

A.M. Ryniewicz, J. Skrzat, A. Ryniewicz, W. Ryniewicz, J. Walocha
Folia Morphol 2010;69(3):147-153.

open access

Vol 69, No 3 (2010)
ORIGINAL ARTICLES
Published online: 2010-08-02
Submitted: 2012-02-06

Abstract

This study investigates if atlanto-occipital fusion affects the size and geometrical configuration of the articular facets of the atlanto-axial joint. Morphometric analysis was performed on the male adult skull, the occipital bone of which is assimilated with the first cervical vertebrae (the atlas). The perimeter, Feret’s diameter, surface area, and circularity of the inferior articular fa-cets were measured. However, we did not observe significant bilateral differences in size of the inferior articular facets of the assimilated atlas compared to normal first cervical vertebrae. Geometrical conformation of the articular facets of the atlas and axis was assessed using a coordinate measuring machine (PMM - 12106, Leitz). The results obtained from this machine indicated that the inferior articular facets of the assimilated atlas presented asymmetrical orientation compared to the normal anatomy of the atlas. Hence, in the case of occipitalization, the gap between the articulating facets of the atlas and the axis was measured to be greater than in the normal atlanto-axial joint. Computer assisted tomography was applied to visualise the anatomical relationship between the inferior articular facets of the assimilated atlas and the corresponding facets located on the axis. In this case, radiographic examination revealed that the bilaterally articulating facets (inferior and superior) showed disproportion in their adjustment within the lateral atlanto-axial joints. Thus, we concluded that the fusion of the atlas with the occipital bone altered the geometry of the inferior articular facets of the atlas and influenced the orientation of the superior articular facets of the axis.
(Folia Morphol 2010; 69, 3: 147-153)

Abstract

This study investigates if atlanto-occipital fusion affects the size and geometrical configuration of the articular facets of the atlanto-axial joint. Morphometric analysis was performed on the male adult skull, the occipital bone of which is assimilated with the first cervical vertebrae (the atlas). The perimeter, Feret’s diameter, surface area, and circularity of the inferior articular fa-cets were measured. However, we did not observe significant bilateral differences in size of the inferior articular facets of the assimilated atlas compared to normal first cervical vertebrae. Geometrical conformation of the articular facets of the atlas and axis was assessed using a coordinate measuring machine (PMM - 12106, Leitz). The results obtained from this machine indicated that the inferior articular facets of the assimilated atlas presented asymmetrical orientation compared to the normal anatomy of the atlas. Hence, in the case of occipitalization, the gap between the articulating facets of the atlas and the axis was measured to be greater than in the normal atlanto-axial joint. Computer assisted tomography was applied to visualise the anatomical relationship between the inferior articular facets of the assimilated atlas and the corresponding facets located on the axis. In this case, radiographic examination revealed that the bilaterally articulating facets (inferior and superior) showed disproportion in their adjustment within the lateral atlanto-axial joints. Thus, we concluded that the fusion of the atlas with the occipital bone altered the geometry of the inferior articular facets of the atlas and influenced the orientation of the superior articular facets of the axis.
(Folia Morphol 2010; 69, 3: 147-153)
Get Citation

Keywords

occipitalization; atlas; cervical vertebrae; craniovertebral joint

About this article
Title

Geometry of the articular facets of the lateral atlanto-axial joints in the case of occipitalization

Journal

Folia Morphologica

Issue

Vol 69, No 3 (2010)

Pages

147-153

Published online

2010-08-02

Bibliographic record

Folia Morphol 2010;69(3):147-153.

Keywords

occipitalization
atlas
cervical vertebrae
craniovertebral joint

Authors

A.M. Ryniewicz
J. Skrzat
A. Ryniewicz
W. Ryniewicz
J. Walocha

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