coccyx
Meaning of coccyx: The coccyx, or tailbone, is the small triangular bone at the base of the spine formed from several fused segments.
Definition of coccyx
The coccyx, commonly called the tailbone, is the small, triangular bone located at the very base of the spine, just below the sacrum. It is formed from several small vertebral segments that fuse together, and it represents the lowest and final segment of the vertebral column.
The coccyx serves as an attachment point for several pelvic floor muscles and ligaments that support structures within the pelvis, and it also helps distribute weight when a person is seated, particularly when leaning backward. Despite its small size, it plays a meaningful role in pelvic support and posture while sitting.
Because the coccyx sits in an exposed position at the base of the spine, it is vulnerable to injury from a fall onto a hard surface or from childbirth, and pain arising from this area, called coccydynia, can be aggravated by sitting or by the pressure of prolonged contact with a hard seat.
Also known as
Used in a sentence
The patient reported persistent coccyx pain after a fall onto a hard surface.
Good to know
Pain localized to the coccyx, called coccydynia, is typically worsened by sitting and often follows a fall or childbirth, distinguishing it from lower back pain arising higher in the spine.
Word origin
Where “coccyx” comes from
Formed from Greek kokkyx, meaning cuckoo, a name given because the bone's curved shape was thought to resemble a cuckoo's beak.