The causes of numbness on the left side of the patient’s head consider the following aspects: First, consider the relationship with the patient’s neurological weakness, if the patient has anxiety, tension, depression, in the case of lack of sleep, poor rest will easily appear the symptoms of numbness on the left side of the head. Secondly, it is considered to be related to the lack of blood supply to the brain, and the patient has numbness of the scalp and head. Thirdly, it may be related to the cold and wind, for example, the patient’s hair is not dry after washing, and the wind blowing on the left side of the head will lead to the symptoms of numbness on the left side of the head. The fourth aspect may also be related to cervical spondylosis, when the patient is in a position for too long, it will lead to the neck muscles in a state of strain. Tension in the neck muscles will cause strain on the scalp, so that the fascia under the patient’s scalp is in a state of tension and contraction, which has a certain impact on the subcutaneous nerves and blood vessels, leading to the symptoms of numbness on the left side of the head.