Tailbone fracture for 4 months with a crushing feeling may be caused by fracture delay and fracture non-union at the fracture site, soft tissue injury around the fracture and other factors. 1. Delayed healing of fracture and non-union of fracture: After the tailbone fracture, if you do not follow the doctor’s instruction or professional treatment, it will lead to poor healing of fracture, delayed healing of fracture or even non-union of fracture, which will cause displacement of fracture to the surrounding area under the pulling of external force and then it will press and stimulate the rectum, resulting in distention feeling. 2. Soft tissue injury around the fracture: activity will increase the friction between the fracture and the surrounding tissue, which will lead to aseptic inflammation of the muscle and fascia around the fracture, and then there will be swelling after four months of fracture. In order to clarify the cause of the swelling sensation four months after the fracture, it is recommended to go to a regular hospital for consultation.