A radiographic study of the human fetal spine. II. The sequence of development of ossification centres in the vertebral column

Textbook descriptions of ossification of the developing spine in the human fetus suggest that the neural arch centres first appear in the upper cervical vertebrae, followed by centres in successively lower vertebrae. Ossification centres for the centra are said to appear first in the lower thoracic region and spread from here to progressively higher and lower levels (Gray, 1973). Published descriptions appear to be based on the examination of small numbers of fetuses; the results of the present study, involving examination of a series of 195 unsexed human fetuses, challenge conventional descriptions regarding the pattern of ossification. The findings, moreover, suggest that the pattern of ossification can be correlated with the muscular activity associated with fetal movements.