A bulge in the tailbone may be a normal physiological structure, or it may be due to disease factors, such as tumors and inflammation of the soft tissues or bones. The spine itself has a physiological curvature, if the body is thin, in the sacrococcygeal part of the spine, you can usually feel the normal bump of the bone. If there is no pain or discomfort when palpating this bulge, and the texture is as hard as bone, then it is a normal physiologic structure. If there is pain on pressure and redness, swelling and heat in the surrounding soft tissues, then tuberculosis or a bone tumor cannot be ruled out. If it is not a bony bump but a soft tissue mass, it may be a lipoma, sebaceous cyst, or sacrococcygeal hidden hair sinus. If there is a bulge in the tailbone and combined with other discomforts, you can visit the doctor for ultrasound examination, combined with the doctor’s examination for definite diagnosis and treatment.