Comparative anatomy of the baboon and the human cervical spine.

Abstract

The anatomy of baboon and human cervical spines were compared by measuring adult, cadaveric specimens. The objective of the study was to compare human and baboon cervical motion segments to determine whether the baboon provides a suitable model for spinal research. Several studies have examined the quantitative anatomy of the human cervical bones and ligaments. Several animal species have been used for cervical spine research; however, no studies have validated whether the animal models resemble the human cervical spine closely enough to provide generalizable data. Multiple morphologic parameters were measured directly from nine baboon and six human adult cadaveric cervical spine specimens. The bone structure and geometry of each of the seven cervical vertebrae were analyzed; the structure and histology of the ligaments were measured; and histomorphometry of the vertebrae was performed. The architectural composition and geometry of individual cervical vertebrae of baboons and humans were similar at each level. The proportional relationship of bone and ligament structures in the two species was almost identical. There were, however, several differences: 1) The baboon spine was about half the size of the human spine; 2) its vertebral arteries were encased fully within the C1 lateral mass; 3) its uncovertebral joints were more prominent; 4) its vertebral endplates were more concave; 5) its pedicles were thinner; 6) its transverse processes were longer; and 7) its spinous processes were horizontal and nonbifid. The geometry and anatomy of the baboon cervical spine closely resemble that of the human cervical spine. It therefore provides an excellent model for in vivo and in vitro research.