Four-year-old leg numbness, may be related to physiological factors, may also be due to hypocalcemia, Guillain-Barre syndrome and other causes. 1. Physiological factors: For example, if a four-year-old child is in a cold environment for a long time, resulting in prolonged cold stimulation of the legs, or if he or she remains in a squatting position for a long period of time, the blood circulation in the legs may not be smooth, thus causing numbness in the legs. 2. Hypocalcemia: If a four-year-old child has hypocalcemia, resulting in low calcium levels in the blood, it may cause numbness in the legs, which may be accompanied by leg cramps, numbness of the lips, tingling and other symptoms. 3. Guillain-Barre Syndrome: If a four-year-old child suffers from Guillain-Barre Syndrome, the peripheral nerves and spinal nerve roots are often damaged, which may cause numbness in the legs, accompanied by sensory abnormalities, flushing and other symptoms. Numbness of the legs at the age of four may also be caused by other reasons. After eliminating physiological factors, it is recommended to consult a doctor as soon as possible to confirm the diagnosis of the cause, and then give targeted treatment and conditioning.