The most common diseases encountered in orthopaedic clinics are not fractures or sports injuries, but various kinds of low back pain and low back pain. There are many clinical causes of low back pain, so today we will briefly talk about the common causes of low back and leg pain. 1, lumbar muscle strain Simple low back pain, rarely leg pain and other symptoms, is also the most encountered in outpatient clinics. Humid and cold climate is one of the most common causes, chronic strain injury is another important pathogenic factor, low back muscles, fascia damage after fibrotic changes, so that the soft tissue is in a state of high tension, resulting in tiny tearing injury, and finally the increase in fibrous-like tissue, contraction, squeezing the local capillaries and peripheral nerves appear pain. Others such as IT and other white-collar workers who sit in the office for a long time, drivers and so on. The main manifestation is diffuse dull pain in the low back, especially more obvious in the lumbar muscles on both sides and above the iliac crest. The pain, coldness, numbness of the skin, muscle spasms and movement disorders in the lower back. X-ray imaging is generally unremarkable, and there may be changes in the lumbar spine curvature such as straightening. Treatment is based on rest and switching positions, supplemented by closure therapy, acupuncture therapy, physiotherapy, massage therapy, ointment, muscle relaxation drugs and anti-inflammatory and pain-relieving drugs are available when symptoms are obvious, with obvious effects. It is recommended not to sit and stand for a long time, and to participate in physical exercise more often. 2, lumbar intervertebral disc herniation lumbar pain with lower limb radiating pain or numbness is the most common symptom. The patient often has a history of lumbar sprain and severe lumbar pain after the injury, which can be tolerated in mild cases and bedridden in severe cases with difficulty in turning over. Symptoms can be seen after bed rest pain relief. Discomfort or pain in the legs is felt after a few days or weeks, and is common in the following lumbar segments with disc herniation: lumbar 4, lumbar 5 and sacral 1 nerve root compression and pain in the area of sciatic nerve innervation, manifested as numbness or radiating pain along the affected hip, posterior thigh, lateral calf and lateral part of the foot. Examination X-rays may reveal degenerative changes in the lumbar spine and narrowing of the intervertebral space. CT scan of the intervertebral disc can reveal disc herniation, but it is not as clear as MRI. It is recommended that after the diagnosis of disc herniation is confirmed, MRI examination should be improved to comprehensively evaluate the disc herniation staging and determine whether there are indications for surgery. Indications for surgery: ① a history of more than three months, strictly conservative treatment is ineffective or conservative treatment is effective, but frequent recurrence and heavy pain; ② the first attack, but the pain is severe, especially in the lower extremities, the patient has difficulty moving and sleeping, and is in a forced position; ③ combined with the expression of cauda equina compression; ④ the appearance of single nerve root paralysis, accompanied by muscle atrophy and muscle strength loss; ⑤ combined with spinal stenosis. The specific procedure will not be discussed. In contrast, patients who are young, have a first attack or have a short duration of disease; those with mild symptoms and whose symptoms can be relieved on their own after rest; and those without obvious spinal stenosis on imaging are recommended to be treated conservatively first: (1) Absolute bed rest During the first attack, bed rest should be strictly applied, emphasizing that neither bowel movements nor urination should be performed by getting out of bed or sitting up. After 3 weeks of bed rest, you can get up and move around under the protection of wearing a lumbar girth, and do not bend over and hold things for 3 months. This method is simple and effective, but more difficult to adhere to. After remission, the lumbar back muscle exercise should be strengthened to reduce the chance of recurrence. (2) Traction therapy The use of pelvic traction can increase the width of the intervertebral space, reduce the internal pressure of the intervertebral disc, the protruding part of the disc retracts, and reduce the irritation and compression of the nerve root, which needs to be carried out under the guidance of a professional doctor. (3) Physiotherapy, massage and tui-na can relieve muscle spasm and reduce the pressure within the intervertebral disc, but note that violent massage and tui-na can lead to aggravation of the disease and should be done with caution. (4) supportive treatment glucosamine sulfate and other drugs 3, thoracic, lumbar vertebral tuberculosis This disease is mostly secondary lesions, patients often have a history of tuberculosis or a history of exposure to tuberculosis. Its lower thoracic section of thoracic or lumbar vertebral tuberculosis presents symptoms such as lumbar pain or numbness very similar to lumbar disc herniation, but the duration of the disease is long, and some of the pain sites are not consistent with the lesion site, often complaining of lumbar pain, often resulting in easy to miss the diagnosis. Patients often have the systemic reactions of tuberculosis, such as low fever, night sweats, wasting, and weakness. Local pressure pain is not obvious, but local percussion can cause pain. Postural abnormalities (positive pick-up sign). Examination X-ray: shows blurring and narrowing of the vertebral space, bone destruction at the relative edges of the vertebral body, and even cavity formation. Need to improve CT and MRI examination, vertebral body occupying lesions are more common with tuberculosis, then improve the tuberculosis-related examination and laboratory tests. 4.Intravertebral tumor Intravertebral tumor is a completely different disease from lumbar disc herniation. X-rays and CT examinations can easily lead to missed diagnosis, so myelography or MRI is the best examination method. After the diagnosis is clear, surgery is the main treatment for intraspinal tumors. 5. Ankylosing spondylitis Ankylosing spondylitis, common in young men, is hereditary. It is a chronic inflammatory disease that mainly involves the spine, the medial skeleton and the large joints of the extremities, and is characterized by fibrosis, ossification and joint ankylosis of the intervertebral discs and adjacent connective tissue. Because of the slow development of the lesion, early diagnosis of ankylosing spondylitis is difficult, but early diagnosis and treatment is the key to reducing the disability rate of the disease. In addition to low back pain can be accompanied by stiffness and pain in the chest and back, neck and lower limb joint pain, the lesion site after prolonged rest stiffness, after activity to reduce or disappear; physical and laboratory tests: X-ray examination shows ankylosing spondylitis sacroiliac joint blurred or narrowed, the symptoms are obvious when the blood sedimentation is elevated, rheumatoid factor test is often positive. The diagnosis is easier when there is obvious ankylosis of the lumbar or dorsal neck and lower limb joints in the middle and late stages of spondylitis, and the X-ray shows bamboo-like changes in the lumbar spine. There is no good treatment at present, and symptomatic treatment with pain relief is the mainstay. 6, aseptic ischemic necrosis of femoral head The early symptoms of aseptic ischemic necrosis of femoral head are pain in the front, lateral and hip of hip joint, which is aggravated after activity, and some patients have pain in the front inner thigh and front inner knee joint, which is similar to lumbar disc herniation. However, the lumbar symptoms and signs of femoral head ischemic necrosis are not obvious, the neurological examinations such as straight leg raising test and strengthening test, thumb dorsiflexion test and flexion and neck test are negative, and there are no neurological changes such as limb sensation, motor disorders or reflex changes, while the hip joint area has obvious pressure pain and percussion pain, and passive movement of the hip joint can induce pain, the 4-letter sign test is positive, and the hip joint movement is limited in the middle and late stages. Further X-ray and MRI examination of both hips can confirm the diagnosis. 7, lumbar spine slippage and spinal stenosis Lumbar spine isthmus discontinuity and slippage is one of the common causes of lumbar leg pain. In patients with simple lumbar isthmus discontinuity and slippage, the main symptom is lumbar pain, which may occasionally spread to the buttocks or thighs, aggravated by exertion and relieved by bed rest, very similar to lumbar disc herniation, but without signs of nerve damage. In combination with spinal stenosis, in addition to low back pain, it is often accompanied by pain, numbness or weakness in one or both lower limbs, mostly with intermittent claudication, and there may be varying degrees of nerve root or occasionally cauda equina damage. Examination: lumbar flexion hyperextension, lumbar spine with step-like changes, local pressure pain, no obvious radiological pressure pain. x-ray and MRI examination can clarify the diagnosis. 8, lumbar spinal stenosis Lumbar spinal stenosis is mostly seen in middle-aged and elderly people over 40 years old, with a slow onset, different from the often sudden onset of central disc herniation. The main symptoms are long-term lumbago, leg pain and intermittent claudication, and lumbago is only manifested as lower back and sacral pain, which is aggravated when standing and walking, and alleviated when squatting, sitting and hip flexion in lateral position; leg pain is mainly due to sacral nerve root compression, often involving both sides, and is not aggravated when coughing, but aggravated when walking, or accompanied by abnormal sensation and motor weakness of lower limbs. In the case of lumbar disc herniation, there is no intermittent claudication, and the symptoms are aggravated by walking, standing and coughing, and the straight leg raise test and strengthening test are positive. x-ray and MRI examination can help to identify the lumbar spine and spinal canal.