Related Experiment Video
Updated: Jul 6, 2026

Precision Measurements and Parametric Models of Vertebral Endplates
Published on: September 17, 2019
Principal components analysis of the atlas vertebra
Christopher A Meseke1, Stephen M Duray, Sebastien R Brillon
1Academic Affairs, Palmer College of Chiropractic, Florida Campus, Port Orange, Fla 32129, USA. christopher.meseke@palmer.edu
Objective:
This project explored morphological asymmetry of the atlas by comparing multiple structural variables bilaterally using multivariate statistics.
Methods:
Two hundred thirty-seven atlases were obtained from the Hamann-Todd Osteological Collection (Cleveland Museum of Natural History, Cleveland, Ohio). The following dimensions were bilaterally measured: anteroposterior length of the superior articular facet, width of the superior articular facet, length of the transverse process, width of the vertebral canal, anteroposterior diameter of the inferior facet, height of the lateral mass, transverse diameter of the inferior articular facet, width of the inferior lateral mass, slope of the inferior facet, convergence angle of the superior facet, circumference of the inferior articular facet, and circumference of the superior articular facet. Principal components analysis (varimax rotation) was used to determine sources of variation within the dataset. Multivariate analysis of variance and paired t tests were used to identify statistical differences between right and left sides for each variable.
Results:
More than 99% of variance was accounted for across 11 eigenvectors, with most eigenvectors dominated by a single variable. Bilateral comparison of variables showed a significant difference between sides for the anteroposterior length of the superior facet, the width of the superior facet, the width of the vertebral canal, anteroposterior diameter of the inferior facet, and convergence angle of the superior facet (all significant at P < .05).
Conclusion:
Based on statistical analysis of the atlantal variables, vertebral canal width and the morphology of the superior and inferior articular facets showed significant asymmetry. The role of these asymmetries related to the biomechanics of the C0 through C1 and encroachment on the spinal cord warrant further investigation.
Related Concept Videos
General Structure of a Vertebra
Articulations of the Vertebral Column
Vertebral Column: Regions and Curvature
Regions of the Vertebral Column
In an adult, the spine is subdivided into five regions: the cervical, the thoracic, the lumbar, the sacral, and the coccygeal region. The spine initially develops as a series of 33 vertebrae; after 20 years of age, the nine bones in the sacral region, five sacral, and four coccygeal bones fuse to form the...
Overview of the Axial Skeleton
The axial skeleton of the adult...
Muscles of the Vertebral Column
Superficial Layer:
The superficial layer consists primarily of the splenius muscles, which include the splenius capitis and splenius cervicis. These muscles are mainly responsible for the head and cervical spine movements, including extension, rotation, and lateral bending. The splenius capitis...
Structural Joints: Cartilaginous Joints
There are two types of cartilaginous joints:
Synchondrosis
A synchondrosis ("joined by cartilage") is a cartilaginous joint where bones are connected by hyaline cartilage. Synchondrosis may be temporary or...