Left foot numbness may be caused by the following reasons: first, lumbar disc herniation, lumbar disc herniation can compress the nerve root and lead to foot numbness. Second, lumbar spinal stenosis, when the lumbar spinal stenosis, protruding discs and hyperplasia of bone spurs irritate and compress the nerve root, which leads to numbness of the foot symptoms. Third, pyriformis syndrome, pyriformis syndrome can compress the sciatic nerve in severe cases, leading to numbness of the left foot, which should be diagnosed and treated with relevant physical examination and neuromuscular electromyography. Fourth, toe neuritis or toe neuroma, when there is toe neuritis and toe neuroma, there can also be numbness of the toes all the time, this time to carry out relevant physical examination for diagnosis and treatment. Fifth, peripheral nerve compression, such as the common peroneal nerve in the walkway of the compression of the symptoms can occur when the foot has been numb, this time to carry out the relevant physical examination and electromyography for diagnosis and treatment.