The cause of a coccyx injury is largely determined based on a medical history and a physical examination. Occasionally, x-rays are taken.

* The entire vertebral column (spine) may be examined. A neurologic examination may be performed. A rectal examination may also be performed. For this exam, the physician inserts a finger into your rectum to feel the area of the coccyx and determine if there is a dislocation or a fracture that can be felt and if direct pressure against the coccyx reproduces your pain.

* Rarely, if the cause of discomfort is unknown, a local anesthetic may be injected into the coccyx to determine whether the origin of the pain is from the coccyx or another part of the vertebral column.

* X-rays may be taken to determine whether there is a fracture or dislocation. However, x-rays occasionally may not reveal these injuries. Some physicians recommend x-rays in both the standing and seated positions to better determine the presence of a fracture or dislocation.