I often see some patients ask this question: My leg is like a tendon pulling pain, but my waist does not hurt, how can I say that this disease is from the waist? Or some patients ask: Isn’t the lumbar disc growing on the waist, so what does it have to do with the leg? I have seen such a patient in the clinic, the right lower extremity radiating pain and numbness for half a year, home in a remote rural area, spent thousands of dollars to see many places, many femur, tibia and fibula films, because the patient thought his disease is leg problems, refused to do the waist examination, spent a lot of money, suffered a lot of suffering. It can be said that this patient is rather paranoid, but there are really many patients who do not understand why they have leg pain. The human spinal cord is like the main road in a city, if this road is blocked, the city will be paralyzed. But this spinal cord is not throughout the spine, at about the level of the first lumbar vertebra the spinal cord is gone, replaced by a bundle of cauda equina nerves, in each segment will send a nerve root to each side, each nerve to be in charge of an area of pain, touch, temperature, position and movement. The nerve roots from the lumbar spine mainly consist of the femoral nerve, the foramen ovale nerve and the sciatic nerve, which innervate the motor sensation of both lower extremities, but not the motor sensation of the lower back. For example, if it is a lumbar 4-5 disc herniation, the main compression is on the lumbar 5 nerve root, then the patient’s main symptoms are the problems in the lumbar 5 innervation area, such as radiating pain along the outer thigh and outer calf to the bunions, numbness in the inner dorsum of the foot and outer calf, weakness in the dorsal extension of the bunions and ankle joints, etc. So don’t just think of lumbar disc herniation when you have back pain, in fact very few patients with simple back pain are actually suffering from lumbar disc herniation, and it is the symptoms of the lower limbs and feet that need special attention, typical of lumbar disc herniation.