The pelvic spine consists of the sacrum and coccyx. These regions are called the cervical spine, thoracic spine, lumbar spine, sacrum, and coccyx. Pain at the coccyx (tailbone) is known as coccydynia. The vertebrae of the sacrum and coccyx are usually fused and unable to move independently. The coccyx, or tailbone, is the remnant of a lost tail. It extends over the lower part of the posterior surface of the sacrum and coccyx. Because the sacrum and coccyx are fused, they are not often used to provide location. The tail has separate vertebrae unlike the fused urostyle or coccyx in modern frogs. The coccygeal fossa marks the deepest part of the pelvic floor, next to the coccyx. Burstyn also injured her coccyx, which led to permanent injury to her spine. Coccydynia is also known as coccygodynia, coccygeal pain, coccyx pain, or coccalgia. Most anatomy books incorrectly state that the coccyx is normally fused in adults. Another method is proper safety equipment for sports is to prevent coccyx pain. However, people who are obese are at a higher risk for developing coccyx pain. These release tension built up around the muscles in the coccyx.