It is clinically common, especially after a fall on the buttocks, and has a significantly higher incidence in women than in men. The caudal plexus, composed of sacral 5, caudal 1 and some of the anterior branches of sacral 3 and 4 nerves, mostly coincides with the fibers below the paravertebral sympathetic trunk. Its branches are as follows: 1. The muscular branch is distributed to the anal raphe. 2. The sensory branches have 3 to 5 tiny anal caudal nerves distributed to the caudal region and perianal skin. Brachial plexus neuralgia should be differentiated from shoulder arthritis and periarthritis. In the latter, the pain is mainly located in the shoulder and upper arm, and the pain does not radiate, while the movement of the shoulder joint is obviously limited and the pain increases, while the movement of the neck does not increase the pain. In patients with periarthritis, shrugging occurs when the upper extremity is abducted because of impaired movement of the shoulder glenohumerus. Treatment of caudal plexus pain is divided into non-surgical and surgical treatments. For non-surgical treatment, the caudal fracture dislocation can be repositioned through anal diagnosis at an early stage, supplemented by physiotherapy, acupuncture and closure therapy (including caudal plexus nerve closure) for those caused by trauma. Surgical treatment can be performed to remove the tailbone if it is seriously deformed and the treatment is ineffective for a long time. During surgery, preoperative and postoperative care should be taken to prevent infection; do not injure the anal sphincter during surgery.