Causes of low back pain Everyone has pain throughout their life, some are temporary, such as pain during pregnancy and childbirth, brief pain after a fall, etc. Some pain is long-term, affecting work and life, and this long-term chronic pain requires a visit to the hospital. How does pain arise? Pain is transmitted through peripheral nociceptive receptors (located in our skin, muscles, ligaments and bone surfaces), through peripheral nerves (sciatic nerve is the thickest peripheral nerve in the body), to the spinal cord, and then to the thalamus and cerebral cortex. Pain is a subjective sensation, and although the degree of pain objectively reflects the severity of the lesion, we cannot exclude the interference of the patient’s sensitivity and psychological factors on pain perception. For example, patients suffering from chronic pain for a long time often experience symptoms of depression and anxiety, the presence of which can further aggravate the subjective perception of pain. Common causes of low back pain 1, lumbar muscle strain, ligament sprain, spasm The most common cause of low back pain is injury to the lumbar muscles or strain of the ligaments. Improper posture when carrying heavy objects, obesity, strenuous exercise, etc. can lead to muscle ligament injury. Clinical manifestations are painful spasms of the lumbar muscle, inability to bend, sit down and stand up, get up and sit down. 2, osteoarthritis For people over 40 years old, especially the middle-aged and elderly who are over 100 years old, sometimes back pain is often associated with arthritis of the spine. In addition to the large and small joints of the limbs that we can reach on the body surface, such as the hip, knee and shoulder joints, the spine also has many joints that we cannot see on the body surface, which clinicians used to call “small joints”. At a certain age, lumbar disc degeneration leads to a decrease in height and a decrease in the quality of the cushion between the vertebrae and the vertebrae, leaving these small joints at the back of the spine in a non-physiological state of loading for a long time, similar to the lack of meniscal padding in the knee. The bone surfaces of the joints are in direct contact with each other and are overly compressed, resulting in gradual morphological changes such as hyperplasia and hypertrophy, and in severe cases, joint deformity and clinical manifestations such as back stiffness and pain. Sometimes there is even a misalignment, which can lead to very sharp pain, and the patient feels “like the back is broken, unable to support the weight”. 3, herniated disc (sciatica) A herniated disc is the term we hear most closely associated with low back pain, and is often associated with sciatica. Indeed, a herniated disc is one of the most common human diseases. A normal intervertebral disc is like an inflated tire, surrounded by a very tough rubber-like fibrous ring, and the thing called the nucleus pulposus, which is wrapped in its middle, is a very soft mass containing a lot of water that acts like air in a tire, maintaining the tension of the disc and preventing the tire rubber DD fibrous ring from being worn out. Age, trauma and other factors cause the disc to become dehydrated, gradually resembling a deflated tire, and eventually the rubber ring (annulus fibrosus) breaks down and the nucleus pulposus protrudes due to a “flat tire”. The herniated nucleus pulposus compresses the sciatic nerve and the nerves innervating the lumbar region, causing pain, numbness and low back pain in the lower extremities. Like osteoarthritis, this is a form of aging and degeneration, but it is more acute and often associated with strenuous exercise or heavy lifting. The people involved also tend to be in their 30s and 40s, when they are more active. 4, osteoporosis The dangers of osteoporosis have only been recognized in recent years. As we age, the total amount of bone calcium in the body decreases, and the changes are especially pronounced in postmenopausal women. This makes the bones throughout the body, not just the vertebrae, more fragile, and fractures can occur even from minor trauma. For osteoporotic vertebrae, in severe cases, the vertebrae can be like an empty eggshell, and compression fractures can occur with minor external forces, eventually leading to pain in the low back.