One way of classifying coccydynia is whether the onset was traumatic versus non-traumatic. In many cases the exact cause is unknown and is referred to as idiopathic coccydynia.

Coccydynia is a fairly common injury which can often result from falls, particularly in leisure activities such as cycling and skateboarding.

Coccydynia is often reported following a fall or after childbirth. In some cases, persistent pressure from activities like bicycling may cause the onset of coccyx pain. Coccydynia due to these causes usually is not permanent, but it may become very persistent and chronic if not controlled. Coccydynia may also be caused by sitting improperly thereby straining the coccyx.

Rarely, coccydynia is due to the undiagnosed presence of a sacrococcygeal teratoma or other tumor in the vicinity of the coccyx.

Sagittal coccygeal movement is measured using the angle of incidence—or the angle at which the coccyx strikes the seat when an individual sits down. A smaller angle indicates the coccyx being more parallel to the seat, resulting in flexion (or “normal” movement) of the coccyx. A larger angle indicates the coccyx being more perpendicular to the seat, causing posterior subluxation (or “backward” movement) of the coccyx.