Cervical Anatomy and Pathology - Masses

Section Lateral Masses of the Atlas and the Axis

Closeup of a sagittal section thorough the lateral masses of the atlas and the axis in a normal cervical spine
Close–up of a sagittal section through the lateral masses of the atlas and the axis in a normal cervical spine of a middle–aged male adult. The upper portion of the slide shows, in part, the occipito–atlantal articulation. The joints between the lateral masses of the atlas and the axis have a markedly biconvex configuration and the anterior and posterior joint spaces are occupied by meniscoid synovial folds. The vertical black structure in the lower part of this slide is the vertebral artery. In the angle between the lateral mass of the atlas and the base of the lamina the vertebral artery swings medially, snugly following the superior surface of the lamina. The wall of the artery shows a large yellow atheromatous plaque. Under the Cl lamina a small yellow circle is seen. It represents a fideucial reference marker that was inserted for, 3–D computer graphics reconstruction. At C3 the root lies immediately behind the artery which then is accommodated in an osseous channel in the atlas. The osseous tunnel transmitting the vertebral artery in this specimen is riding high, illustrating that an atlanto–axial screw inserted through the narrow pars interarticularis of C2 could jeopardize the artery.

©2000 Wolfgang Rauschning, M.D., Ph.D.
Professor of Clinical Anatomy
Academic University Hospital
Department of Orthopaedic Surgery
Uppsala, Sweden
Reproduction without permission is prohibited
Updated on: 02/01/10

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