The causes of horizontal lines at the back of the head usually include aging, hard objects or malnutrition. 1. Along with the gradual growth of age, the skin tissue of the back of the brain will also appear aging, which can be manifested as the reduction of subcutaneous elastic fibers and loss of collagen, and then the skin becomes thinner with uneven horizontal lines, which is a normal physiological manifestation and usually does not require special treatment. 2. When the brain tissue is compressed by hard objects for a long time, it is easy to be gradually sunken inward, especially when the bar-shaped hard objects are compressed in the back of the brain, there will be the phenomenon of horizontal stripes, which can be gradually disappeared after the lifting of the compression, and if necessary, can be applied hot compresses or massages to promote the recovery of the local area. 3. When the human body has too little intake or too much consumption, malnutrition is likely to occur, and at this time the subcutaneous fat will be significantly reduced, resulting in the skin of the back of the brain to lose a certain degree of support and the appearance of horizontal stripes. Horizontal stripes on the back of the head may also be caused by other reasons, and it is recommended to go to the hospital if you want to clarify the cause.