The back of the neck bone bulge may be cervical vertebrae protrusion, may also be cervical spondylosis, fat accumulation and other reasons. 1. Cervical vertebrae spinous process: the back of the neck bone bulge may be cervical vertebrae spinous process, is the normal physiological structure of the human body, the body shape is relatively slim and thin people, the back of the neck is not rich in muscle, fat, subcutaneous bone, low head when the bone bulge is more obvious. 2. Cervical spondylosis: prolonged low head to play cell phone, low head to work, keep a posture unchanged may cause cervical vertebrae physiological curvature change and cervical spondylosis, cervical spondylosis patients appear cervical vertebrae joints or cervical vertebrae instability, the back of the neck will be bone bulging phenomenon. 3. Fat accumulation: Some people are obese and have more fat at the back of the neck, and localized fat accumulation is similar to bone protrusion in appearance. If you have headache, pain and other discomfort symptoms, you should consult a doctor to check the cause.