Numbness in the thumbs of the feet may be caused by the following reasons: 1. It may be caused by peripheral neuritis of the feet, which is common when the feet are often cold, or when the feet are exposed to chemicals that cause peripheral neuritis. In addition to the numbness of the thumb, this condition is accompanied by other toes with this symptom. 2, it is possible that lumbar spine diseases compress the nerves of the lower limbs, resulting in numbness of the thumb, commonly due to lumbar disc herniation, lumbar spinal stenosis or lumbar spine slippage, which compresses the nerve roots of the lower limbs, resulting in sensory numbness, weakness, pulling pain and other symptoms of the nerves of the lower limbs. In addition to the numbness of the thumb of the foot, symptoms such as numbness and pain in the back of the foot or the nerve pulling pain in the whole lower extremity may also occur, accompanied by discomfort in the lower back, such as lumbago, lumbago, and even limited lumbar movement.