Coccyx (Os coccygis)
Educational content only — not medical advice.
Anatomy
The coccyx is a small triangular bone at the base of the vertebral column, immediately inferior to the sacrum, formed by the fusion of three to five rudimentary coccygeal vertebrae. It articulates with the sacrum at the sacrococcygeal joint and provides attachment for ligaments and pelvic-floor muscles, notably levator ani and gluteus maximus. It is functionally important in weight-bearing while seated: leaning back transfers part of the body weight onto the coccyx.
Clinical notes
Coccydynia (coccygeal pain) is one of the most common causes of posterior low-back pain, typically after falling onto the lower back or after vaginal childbirth. Coccygeal fracture or dislocation is assessed by rectal examination and dedicated radiographs; most cases are managed conservatively with a donut cushion and anti-inflammatories, and surgical excision (coccygectomy) is a rare last resort for refractory cases.
Related structures
Educational references
FAQ
What is the role of the Coccyx?
The coccyx is a small triangular bone at the base of the vertebral column, immediately inferior to the sacrum, formed by the fusion of three to five rudimentary coccygeal vertebrae. It articulates with the sacrum at the sacrococcygeal joint and provides attachment for ligaments and pelvic-floor muscles, notably levator ani and gluteus maximus. It is functionally important in weight-bearing while seated: leaning back transfers part of the body weight onto the coccyx.
Why is the Coccyx clinically important?
Coccydynia (coccygeal pain) is one of the most common causes of posterior low-back pain, typically after falling onto the lower back or after vaginal childbirth. Coccygeal fracture or dislocation is assessed by rectal examination and dedicated radiographs; most cases are managed conservatively with a donut cushion and anti-inflammatories, and surgical excision (coccygectomy) is a rare last resort for refractory cases.
Source & license
Derived from Z-Anatomy (Gauthier Kervyn et al.), CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/); upstream geometry from BodyParts3D, © The Database Center for Life Science. license details