Caudalgia can be associated with caudal pressure and abnormal activity on anal palpation, and sometimes fracture breaks and displacements can be palpated. Most congenital tailbone deformities are hook-shaped, and this state inevitably causes a state of high tension in the surrounding muscles and ligaments, resulting in pain due to premature degeneration of these tissues. This factor is less common than before. Bone imaging: Bone imaging can diagnose bone tumor and bone metastasis 3-6 months earlier than X-ray examination, but it should be noted that this method is highly sensitive and low specificity. 2.CT examination of bone, joint and soft tissue: CT examination of bone, joint and soft tissue is a method to examine bone, joint and soft tissue by CT. 3, MRI: MRI, also known as magnetic resonance imaging, is the use of nuclear magnetic resonance principle, through the applied gradient magnetic field detection of the emitted electromagnetic waves, according to which the internal structure of the object can be drawn into the image.