Sacrum and Coccyx Anatomy

Overview

This lecture covers the anatomy of the sacrum and coccyx, highlighting key structures and their features.

Sacrum Structure

• The sacrum is part of the axial skeleton and consists of fused vertebrae.
• A vertical ridge along the back is called the median sacral crest.
• Sacral foramina are holes in the sacrum that allow for passage of nerves and vessels.
• Each hole is a sacral foramen (singular); the plural is sacral foramina.
• The sacral hiatus is a distinct opening at the lower end of the sacrum, shaped like an upside-down "U" or "V".

Coccyx (Tailbone)

• The coccyx, or tailbone, is composed of small bones attached to the sacrum.

Key Terms & Definitions

• Sacrum — A triangular bone formed by the fusion of several vertebrae at the base of the spine.
• Median Sacral Crest — A ridge on the posterior surface of the sacrum formed by fused spinous processes.
• Sacral Foramen (plural: foramina) — Openings in the sacrum for nerves and blood vessels.
• Sacral Hiatus — An opening at the lower end of the sacrum.
• Coccyx — The small, bony structure attached to the sacrum, commonly called the tailbone.

Action Items / Next Steps

• Review anatomical diagrams to identify the sacrum, median sacral crest, sacral foramina, sacral hiatus, and coccyx.