Sacrum

A continuation of the vertebral column, the sacrum is composed of five fused vertebrae. Where the sacrum meets with the fifth lumbar vertebra it is widest, decreasing in size inferiorly. The sacrum also makes up the posterior aspect of the pelvic girdle.

• Base
• Apex
• Promontory
• Ventral surface
• Transverse ridges
• Anterior sacral foramina
• Dorsal surface
• Medial sacral crest
• Posterior sacral foramina
• Lateral surface – Wings or ala

Coccyx

Four very small vertebrae found at the apex of the sacrum which are fused in adults, but are often absent in archaeological specimens. The corunae are the only landmarks seen on the coccyx, which are tubercles projecting superiorly from the body of the coccyx.