Answer: 4 fused vertebrae - tailbone
Causes. Coccyx pain is often due to to a dislocation at one of the coccyx joints or stiffness of one of the joints or a spasm of the muscles attached to the coccyx . It can follow after falls childbirth repetitive strain or surgery or for no obvious reason. The pain can disappear by itself or with treatment or it can continue for years and ...
The coccyx is formed of either three four or five rudimentary vertebrae.It articulates superiorly with the sacrum.In each of the first three segments may be traced a rudimentary body and articular and transverse processes; the last piece (sometimes the third) is a mere nodule of bone.
The coccyx is an inverted triangle with the base (wide part) at the top and the apex (pointy end) at the bottom. Even before the fusion of the coccyx is complete all but the first coccygeal vertebrae are little more than underdeveloped vertebrae that look a bit like nodules of bone rather than independent structures.
Tailbone pain — pain that occurs in or around the bony structure at the bottom of the spine ( coccyx ) — can be caused by trauma to the coccyx during a fall prolonged sitting on a hard or narrow surface degenerative joint changes or vaginal childbirth.
The coccyx also known as the tailbone is a small triangular bone resembling a ...