Coccydynia, also sometimes known as coccygodynia, is the medical term for pain around the coccyx. The coccyx is the last bone at the base of the spine.
The pain of coccydynia can range from mild to severe, and it is often worse when sitting down.
The coccyx
The coccyx is sometimes referred to as the 'tail bone' because it is the last remaining part of the full tail that belonged to our ape-like ancestors. The coccyx is located just above the cleft in the buttocks, and it curves forwards so that it points towards the front of the body.
The coccyx is made up of three small bones. The bones of the coccyx are loosely fused together. They become more flexible in pregnant women so that they are able to give birth more easily.
The coccyx has two main functions:
- it serves as a weight-bearing structure when somebody is sitting down
- it is an important attachment site for various muscles, tendons and ligaments
How common is coccydynia?
Coccydynia is an uncommon cause of back pain. It accounts for less than 1 out of every 100 cases of lower back pain.
Women are five times more likely to develop coccydynia than men. It is thought that the reason for this is that giving birth can sometimes damage the coccyx, leading to coccydynia. The coccyx is also more exposed in women, which makes it more vulnerable to damage and injury.
Other causes of coccydynia can include:
- trauma to the coccyx, resulting from a fall or other type of accident
- pulling the coccyx out of its normal position, either through poor posture or repeated activity or motion, such as cycling or rowing
In around a third of cases of coccydynia, no obvious cause can be found.
Outlook
The outlook for coccydynia is usually good. In some people, the pain will resolve within a few weeks.
In others, the pain can persist for several months (chronic coccydynia). Chronic coccydynia can usually be treated using painkillers and physiotherapy.
However, a small number of people with chronic coccydynia do not respond to treatment and may require surgery to remove some or all of their coccyx. See Coccydynia - treatment for more information.
