The tailbone, consisting of three to five fused vertebrae at the very bottom of the spine. It serves as an attachment point for muscles, tendons, and ligaments involved in pelvic floor function and provides support when sitting.
From Greek 'kokkyx' meaning cuckoo, because the bone's curved shape resembles a cuckoo's beak. This whimsical naming by ancient Greek anatomists reflects their practice of using familiar objects to describe body structures.
Your coccyx is a vestigial tail - evolutionary evidence that our ancestors once had tails like other primates! Though small, a broken coccyx (often from falling on your tailbone) can be incredibly painful because it's surrounded by muscles you use every time you sit, stand, or go to the bathroom.
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