A circle of horizontal bulge at the back of the neck may be physiological bulge, or fat accumulation in the neck, or it may be lipoma. 1. Physiological bulge: cervical spinous process, generally the seventh cervical spinous process will be extended backward bulge, especially the body type of thin people, in the low head will be very obvious, no pain, no itch, usually do not feel, belong to the physiological phenomenon, do not need to worry about it. 2. Neck fat accumulation: usually seen in obese people, fat accumulation in the back of the neck will appear fat hyperplasia, manifested as a circle behind the neck of the horizontal bulge, usually also appear in the neck discomfort symptoms. 3. Lipoma: the lump formed by subcutaneous fat hyperplasia in the neck, inside is adipose tissue, outside there is a layer of membrane to wrap it up, forming a circle of horizontal bumps. It is recommended to go to a regular hospital to clarify the cause of the disease.