A 15-year-old boy with a bulging bone behind the ear may have physiological factors or pathologic factors such as enlarged lymph nodes behind the ear. 1. Physiological factors: 15-year-old boy if more thin, less subcutaneous fat, may be able to feel the bone protrusion, resulting in the bone behind the ear bulge. This is a physiological phenomenon. 2. Behind the ear lymphadenitis: lymphadenitis if the oozing is more obvious, with the surrounding tissue to produce adhesion, the texture can also be more hard, at this time to feel the bone like there is a bulge, in fact, for the lymph nodes are enlarged. 15-year-old boy behind the ear bone protrusion, there are other reasons (such as trauma, etc.), it is recommended to consult a doctor in a timely manner to find the cause, with the doctor active treatment.