- 3 Ossification centers:
- 1 (sometimes 2) for body (not ossified at birth; appears on X-ray during 1st yr)
- 1 for each neural arch (appear bilaterally ≈ 7th fetal week)
- Synchondroses:
- synchondrosis of the spinous process: fuses by ≈ 3 yrs of age
- 2 neurocentral synchondroses: fuse by ≈ 7 yrs of age
- The ossification centers of C1 fail to completely close in 5% of adults (usually posteriorly).
- When present, the rare anterior defect is usually associated with a posterior defect
