Numbness of a muscle in the lateral thigh may be caused by physiological factors such as sedentary or squatting, or it may be caused by pathological factors such as lateral femoral dermatitis, lumbar disc herniation, and diabetic peripheral neuritis. 1. Physiological factors: if sedentary or squatting for a long time will lead to the lateral thigh nerve is compressed, the symptoms of a piece of muscle numbness in the lateral thigh. This is a normal physiological phenomenon, and the symptoms will usually improve after changing the posture. 2. Lateral femoral cutaneous neuritis: Lateral femoral cutaneous neuritis is considered to be caused by traumatic nerve damage to the thigh and compression of the lateral femoral cutaneous nerve. Numbness of sensation in the lateral thigh, loss of superficial sensation or disappearance of sensation will often occur, so the patient will show numbness of a muscle in the lateral thigh. 3. Lumbar disc herniation: Lumbar disc herniation may be caused by disc degeneration, lumbar spine injury, heredity and other reasons. Numbness of the lower limbs, decrease in muscle strength of the lower limbs, intermittent claudication and other symptoms often occur, so the patient will have a numbness of a muscle on the outer thigh. 4. Other: patients with a muscle numbness of the lateral thigh is also considered to be diabetic peripheral neuritis, cerebral infarction and other diseases. If the symptoms continue to be unrelieved, it is recommended to go to the hospital in a timely manner, under the guidance of the doctor to standardize the treatment.