Should the Coccyx Bones be Fused Together? Does that Cause Tailbone Pain?

Should the Coccyx Bones be Fused Together? Does that Cause Tailbone Pain?
  • There is a lot of variability from person to person regarding fusion of the coccygeal joints.
The Completely Fused Coccyx: A Rigid, Non-mobile Tailbone
  • In some people, the entire coccyx is fused, meaning that the individual bones of the coccyx are fused into one solid bone.
  • When this happens, there is no mobility or movement possible. In that situation, the tailbone is stiff or rigid.
  • A stiff, rigid coccyx is not able to move out of the way when you sit. So, it may be more prone to pressure and pain while sitting.
The Completely Patent Coccyx: a Tailbone where None of the Joints are Fused
  • In other people, the individual joints may all be patent (not fused).
  • When those joints are patent, it means that there can be movement at those joints.
  • The movement of those joints could be either normal or abnormal, depending on how sturdy the ligaments are.
  • Ligaments attach one bone to the next bone. If the ligaments are torn, stretched, or loose, then there can be excessive movement at the joint (also called hyper mobility or instability).
  • The best way to assess for hypermobility is by doing sitting versus standing x-rays and comparing the position of the tailbone while someone is standing compared with while they are sitting. You can read more about sit-stand coccyx x-rays here at this link.
A Coccyx where SOME Joints are Fused and SOME Joints are Patent
  • Many people have some of their coccygeal bones fused together, while some of their other joints at the coccyx are not fused.
  • The take home message is that this varies from patient to patient.
  • It is important to CORRELATE the imaging findings with the exact site of the patient’s pain.
To get your copy of the book “Tailbone Pain Relief Now!” go to:
For more information on coccyx pain, or to be evaluated at Dr. Foye’s Tailbone Pain Center in the United States, go to:
Patrick Foye, M.D.
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