There are five sacral ribs and five fused vertebrae.
It opposes the cricoid cartilage against the cervical vertebrae, compressing the lumen of the upper oesophagus.
The next stage is, typically, biconcave vertebrae, then wedge-shaped vertebral bodies and, finally, complete compression fractures.
Since all 17 skulls were associated with cervical vertebrae, and in some cases with hyoid bones, the heads evidently were fresh when they were interred.
The separation of vertebrae into caudal and precaudal portions appears rather problematic.
On either side of each vertebra are small projections that enclose an opening.
The vertebra has a neural canal less than half the diameter of the centrum.
Films were slightly better although visualising vertebrae was still difficult.
