File:Human axial skeleton- axis development 01.jpg

Human Axis Development

This is a plate from a historic study of the human axis vertebra.

PLATE IX.

Fig. 1. Upper surface of axis at 11th week x5. a, cartilaginous body; b, bony rod in arch.

Fig. 2. Coronal section of axis at 16th week x2. c, dens; d, bony nucleus in body; other letters as last.

Fig. 3. Coronal section of axis at 19th week. d', united body nuclei; e, densnuclei.

Fig. 4. Similar section at 22nd week.

Fig. 5. Unusual case of delayed union of lateral dens centres in infant of 5 months old.

Fig. 6. Axis at birth. e', united dens centres.

Fig. 7. Axis of child 15 months old, seen from below. f, hypo- chordal nucleus.

Fig. 8. Coronal section of axis of 28 months child, showing hypo- chordal epiphysis.

Fig. 9. Axis of child 45 months old, showing the apical epiphysis, g,of the dens.

Fig. 10. Coronal section of adult axis, showing, h, the lenticular cartilage between the dens and the body of the axis; and, i, the inferior epiphysis of the body.

Reference

<pubmed>17232080</pubmed>| PMC1328386