Spine · Irregular bone
Coccyx (Tailbone)
The coccyx, or tailbone, is the small bone at the very bottom of the spine, formed from a few fused vertebrae. It anchors muscles and ligaments and bears some weight when sitting.
What it is
The coccyx is the remnant of a tail — a small triangular bone of three to five fused vertebrae at the base of the spine.
Where it is
The very bottom of the spine, below the sacrum.
What it does
Provides attachment for pelvic-floor muscles and ligaments and helps support weight when sitting, especially when leaning back.
Connections
Joints and connections
- Joint with the sacrum
When things go wrong
Common injuries and conditions
- Coccyx injury or fracture (from falling onto the bottom)
- Coccydynia (persistent tailbone pain)
Education and reference only. This explains the anatomy in plain terms; it is not a diagnosis. A severe injury, a visibly deformed limb, or the inability to move or bear weight needs urgent assessment — call 999 or go to A&E for a serious injury.
Did you know?
An interesting fact
The coccyx is what remains of the tail our distant ancestors had — a genuine evolutionary leftover.
Answers
Coccyx: frequently asked questions
What is the tailbone?
The tailbone (coccyx) is the small bone at the bottom of the spine, made of a few fused vertebrae. It anchors muscles and bears some weight when sitting.
How long does tailbone pain last?
Tailbone pain (coccydynia), often from a fall, usually settles over weeks to a few months with self-care such as a cushioned seat and pain relief. Persistent pain should be assessed.
Explore the spine
Related bones
Sources
Where this is drawn from
- NHS — Anatomy and body systems
- Gray's Anatomy for Students (Drake, Vogl, Mitchell)
- TeachMeAnatomy — skeletal system
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