X-ray diffraction studies of the arrangement of collagenous fibres in human fetal intervertebral disc.

X-ray diffraction shows that the arrangement of collagenous fibres in the annulus fibrosus of the fetal intervertebral disc is essentially the same as in the adult tissue. Collagen fibrils, when first forming, are apparently laid down with the same orientation as in the adult. Mechanical stress is suggested as a possible morphogenic factor. Mean values for the fibre tilt and its angular spread are calculated for anterior, posterior and lateral regions of the annulus.