Sacral Curvature (convex)
Five components fused together are typically referred to as a compound or a blend.
Sacrum
The five fused vertebrae with which the hip bones move are collectively known as the sacrum. The sacrum forms the posterior wall of the pelvis and connects the spine to the hip bones, providing stability and support for the body.
The five bones fused in the lower back are called the sacrum. The sacrum is a triangular bone located between the two hip bones and forms the back part of the pelvis. It is made up of five separate vertebrae that fuse together during development.
The last 4 fused vertebrae in the spine are called the sacrum. The sacrum is a triangular bone located below the lumbar vertebrae and is formed by the fusion of five sacral vertebrae.
The lumbar vertebrae in the lower back is typically five in number and unfused.
The medical term for the five fused vertebrae above the tailbone is the sacrum.
The human backbone is also called the spine, and it consists of a vertebral column that has many bones. There are seven cervical, twelve thoracic, five lumbar, five fused sacral, and four fused coccygeal bones in an adult. So that makes a total of 33 bones.Read more: How_many_bones_make_up_the_human_backbone
Sacrum
sacrum, it's actually five bones that are fused together.
This is called a Cephalothorax.
Sacrum