Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
The sacral hiatus is an opening at the inferior end of the sacrum, on its posterior surface. This natural opening is formed by the failure of the laminae of the fifth sacral vertebra to fuse.
The triangular bone at the base of the spine, composed of five fused vertebrae, forming part of the pelvis.
Cauda Equina: A bundle of spinal nerves and spinal nerve rootlets, resembling a horse's tail, located at the lower end of the spinal cord, extending from the lumbar spine through to the sacral hiatus.
Lumbar Spine: The lower part of the spine consisting of five vertebrae which are larger than those in other regions of the spine, providing support and stability