Pain in the area of the coccyx (or tailbone) is called coccydynia or coccygodynia, and can be anything from discomfort to acute pain. The name describes the symptoms, but it is really a collection of conditions which can have different causes and need different treatments.
The main symptom is pain during or after sitting. How painful it is also depends on the design of the chair and its padding. Some people get an acute pain while moving from sitting to standing. This symptom is linked to a coccyx that dislocates when you sit. More information about coccyx pain symptoms here.
Tailbone pain can be cured eventually in the great majority of cases, given the right treatment. However, finding a doctor who can do a proper diagnosis of the condition and give effective treatments is difficult, and many people suffer years of pain.
The rotating picture is a female pelvis, including the tops of the leg bones. The coccyx is the small triangular bone hanging down at the bottom of the spine. Although it is padded with flesh, you can see it is quite vulnerable.
The second picture is the dorsal (back) view of a coccyx. It is usually made up of 3 to 5 little bones, some of which may be fused together. The spinal cord ends above the coccyx.
There is more information about the normal coccyx here.
The coccyx can be damaged by falls, by childbirth, by sitting on hard chairs, or the cause may be unknown. The result may be a coccyx bent at 90 degrees to the sacrum, as in the picture.
Or the coccyx may be in a normal position when you stand, but dislocate when you sit.
The damage may be at the joint between the sacrum and the coccyx, or at one of the joints of the coccyx itself.
There is more information about damaged coccyxes here.
Sometimes there is a bony spur, or spicule, on the end of the coccyx. The spur is usually invisible on x-rays, but may be seen on MRI images. The spur points backwards at the tip of the coccyx, and can be felt through the skin. There is usually a corresponding pit in the skin over the spur. Spurs only cause pain in thin patients, who do not have a padding of fat over it.
See more about coccyx spurs.
If muscles attached to the coccyx become taut or spasm, they can pull on the coccyx causing pain. Rectal examination of the pelvic floor muscles is necessary to locate these. Muscles affected include the gluteus maximum, piriformis and coccygeus muscles.
There is more information about tight muscles here.
Famous people who have injured their coccyxes
Author: Jon Miles