Demographic aspects in cervical vertebral bodies' size and shape (C3-C7): a skeletal study

This cross-sectional study was conducted on the skeletal remains of individuals of known sex, age, and ethnic origin. The vertebral bodies of levels C3-C7 were measured and analyzed. Whereas many studies were performed on the size and shape of the vertebral bodies in the thoracic and lumbar spines, few have focused on the cervical vertebral bodies. Thus, there is insufficient data in the literature on the anatomy of the cervical spine, especially based on large study populations.

To establish a large database on cervical vertebral bodies' size and shape and analyze their association with demographic parameters.

The population studied was composed of 277 individuals, adult males and females of African American (AA) and European American (EA) origin. The skeletal remains are housed at the Hamman-Todd Osteological collection (Cleveland Museum of Natural History, Cleveland, OH).

A 3-D digitizer was used to measure the size and shape of the C3-C7 vertebral bodies. Descriptive statistics were carried out for all measurements. t Test and one-way analysis of variance were performed to assess differences in vertebral bodies' size and shape between different demographical groups (by age, sex, and ethnicity).

The vertebral bodies and foramina are significantly wider, more elongated, and higher in males compared to females. AA females and males manifest significantly greater vertebral bodies (width and length) in the upper and midcervical region (vertebrae C3-C5) than EA females and males. Nevertheless, the heights of the C3 and C4 vertebral bodies are significantly smaller among the AA population, regardless of sex. The vertebral foramina's width does not differ significantly between the two ethnic groups, independent of sex, whereas they tend to be elongated in the EA group (significant for C3, C5, C7). For most vertebrae, no significant differences were found in the superior facets' length between AA and EA males and females. Cervical vertebral bodies become wider and more elongated with age, although the changes in the latter dimension are much more pronounced than in the former. Notably, the body shape of the cervical vertebrae changes gradually from a more round shape (C3 length/width index=0.84) to a more oval one (C7 length/width index =0.65). This is due to the fact that the width dimensions increase by almost 40% from C3 to C7, whereas the length dimensions increase only by approximately 10%. Furthermore, there is a significant reduction in body height with age in C3-C6. In contrast, no significant changes in vertebral foramen size with age were found.

The cervical vertebral bodies' shape and size are sex-dependent phenomena, that is, in all parameters studied, the dimensions were greater in males than in females. For the midcervical level, there is a difference in body shape between individuals of different ethnic origins. The cervical vertebral bodies also exhibit considerable size and shape changes with age, that is, they become more elongated (oval shaped), wider, and shorter. In contrast, vertebral foramen size is age independent.