There are many clinical causes of low back pain, which can easily lead to unclear diagnosis or even misdiagnosis due to various factors, and also affect the treatment effect. In order to avoid omission and misdiagnosis in clinical practice, it is required to: take a comprehensive medical history and detailed physical examination as much as possible. Low back pain is a group of syndromes, and when thinking about the problem, we should consider it from many aspects, understand the characteristics of each disease, and analyze it in detail. Emphasize auxiliary examinations. Patients with low back and leg pain should also routinely perform X-ray chest X-ray or chest examination, make routine blood and urine, blood sedimentation, liver and kidney function and blood sugar examination to facilitate the screening of various diseases. About 90% of patients with low back pain can get preliminary diagnosis by routine X-ray plain film examination, and if further examination is needed, myelography, CT and MRI should be selected according to the need. For example, CT is a tomographic image, which can directly observe the bony and soft tissue structures of the vertebral canal, but the scanning range is limited and may miss the segments with lesions that are not suspected at that time; MRI is a three-dimensional imaging with good soft tissue contrast, which can show the whole picture of the lumbar spine and observe the lesions of the intervertebral disc, intervertebral foramen, spinal cord and nerve roots better than CT, and can observe the compression of the spinal cord and nerve roots It can also observe the degree of spinal cord and nerve root compression and the nature of the compressed material. For the diagnosis of bone metastasis cancer, CT and MRI are far more sensitive than X-ray examination, and their efficiency in diagnosing bone metastasis cancer is 80%, and they can often detect the lesion when the patient has no bone pain symptoms or is negative. 1.Lumbar disc herniation Low back and leg pain is the most common symptom, mostly seen in young adults. The patient often has a history of lumbar sprain and severe lumbar pain after the injury, which is tolerable in mild cases but bedridden in severe cases and extremely difficult to turn over. Symptoms can be seen in bed and pain relief. The following lumbar disc herniations are common: lumbar 4, lumbar 5 and sacral 1 nerve root compression and pain in the sciatic nerve innervation area, manifested as numbness or radiating pain along the affected hip, posterior thigh, lateral calf and lateral foot. When the nucleus pulposus protrudes larger or central type protrusion, it can be pain in both lower limbs. In severe cases, it may cause paralysis in the saddle area, difficulty in urination and defecation and bilateral foot paralysis. Clinical examination shows that: lumbar deformity, lumbar disc herniation first has a reduction or disappearance of physiological anterior curvature of the lumbar segment of the spine, and even becomes reverse posterior curvature. As the nucleus pulposus protrudes backward, passive anterior lumbar flexion relieves the compression on the nerve roots. Lateral curvature of the lumbar spine occurs later and is mostly seen in cases where the lumbar pain has lasted longer. When the herniated disc compresses the nerve root inferiorly (axillary type), the spine bends toward the affected side; when the herniated disc compresses the nerve root superiorly (supra-shoulder type), the spine bends toward the healthy side. The functional activity of the lumbar spine is limited; paravertebral pressure and percussion pain with radiating pain; positive straight leg raise test and strengthening test: a positive straight leg raise test on the healthy side indicates a large central disc herniation or an axillary type herniation, while the supra-shoulder type is negative. A positive femoral nerve pull test is a herniated disc in the upper lumbar region. Positive flexion neck test, jugular vein compression test, tendon reflex change: if the nerve root is severely compressed or compressed for too long, its corresponding tendon reflex disappears. Abnormal skin sensation, mainly hypoesthesia or numbness of the skin in the area innervated by the corresponding nerve. The central type herniation compresses the cauda equina nerve, and numbness in the saddle area and dysfunction of the bladder and anal sphincter may occur. The upper lumbar disc herniation then femoral nerve involvement quadriceps muscle weakness, muscle atrophy; sciatic nerve involvement, gastrocnemius muscle tone is weakened, thumb extensor muscle strength is weakened, long duration of the disease dorsal foot extensor muscle group atrophy, tibial anterior ridge protrusion. x-ray examination, MRI, CT examination, etc. can be seen lumbar disc herniation changes, electromyography examination can be seen nerve root damage. 2, thoracic and lumbar vertebral tuberculosis This is mostly a secondary lesion, and the causative factor is Mycobacterium tuberculosis. The patient may have a previous history of tuberculosis or exposure to tuberculosis. Symptoms such as lumbar pain or numbness in the lower thoracic segment of the thoracic or lumbar vertebrae are very similar to those of lumbar disc herniation, but the duration of the disease is long, and some of the pain sites are not consistent with the lesion sites, often complaining of lumbar pain, which often leads to missed diagnosis. Patients are often accompanied by systemic symptoms, such as low fever, night sweats, wasting, and weakness. Local pressure pain is not obvious, but local percussion can cause pain. The posture is abnormally limited. When standing or walking, try to tilt the head and trunk back to reduce the pressure of the weight on the affected vertebrae. Try to bend the knees and hips when picking up things from the ground, avoid bending over, and hold the front of the thighs with your hands when standing up (positive pick-up sign). Cold abscesses may sometimes be palpable in the lower abdomen. Laboratory tests accelerate blood sedimentation, positive for tuberculosis antibodies, X-ray radiographs show blurring and narrowing of the intervertebral space, bone destruction at the relative edges of the vertebral body, central type may have dead bone, cavity formation, surrounding osteoporosis. 3.Intravertebral tumor Intravertebral tumor is a collective term for primary tumors and metastatic tumors growing in the spinal cord itself and the tissue structures adjacent to the spinal cord (such as spinal nerve roots, dura mater, adipose tissue, etc.) within the spinal canal. It is a completely different disease from lumbar disc herniation. When intravertebral tumor compresses the spinal cord and nerve roots, it may have radicular pain similar to lumbar disc herniation, and symptoms such as back and leg pain or numbness may occur. However, one of the typical symptoms of intravertebral tumor is that the pain or sensory abnormalities are persistently and progressively aggravated and not relieved by bed rest; whereas the lumbar pain caused by lumbar disc herniation is persistent, relieved by lying down and aggravated by standing activities. In terms of physical signs, paravertebral and gluteal pressure pain of intravertebral tumor is not obvious, straight leg raise test and straight leg raise strengthening test are not typical, and sensory-motor reflex disorder is often not limited to one nerve root innervation area. Intravertebral canal tumors above lumbar 1 may show manifestations of spinal cord compression with positive pathological reflexes, and cauda equina tumors may have signs of multiple roots or cauda equina nerve compression. In lumbar disc herniation, there is mostly pressure pain at the herniated space and radiation to the lower limbs, and the compression of a single nerve root leads to motor, sensory, and reflex impairment, positive straight leg raise test and straight leg raise strengthening test, positive flexion neck test and jugular vein compression test, positive thumb dorsiflexion muscle strength test, and negative pathologic reflex. For patients with lumbar disc herniation who have neurological changes such as limb sensation, motor disorders or reflex changes, and whose efficacy is not obvious or worsens after systematic conservative treatment, the possibility of intraspinal tumor should be considered and further examination is required. In terms of imaging examination, there are bony changes in X-ray plain film, such as scoliosis, widening of spinal arch spacing and enlargement of intervertebral foramen, etc. However, such changes can only occur in huge tumors, and CT scan diagnosis is more likely to miss and misdiagnose spinal cord tumors due to different examination levels. Some intravertebral tumors, especially lower lumbar tumors, are difficult to distinguish from lumbar disc herniation either by symptoms or physical signs. Therefore, myelography or MRI is the best examination method to determine the approximate lesion site based on symptoms and clinical examination. After the diagnosis is clear, the treatment of intravertebral tumor is mainly surgical, and manipulative treatment is prohibited. 4, ankylosing spondylitis Ankylosing spondylitis is a chronic inflammatory disease that mainly involves the spine, medial skeleton and large joints of the extremities, and is characterized by fibrosis of the intervertebral disc ring and its adjacent connective tissue, ossification and joint ankylosis. 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. Low back pain is the prominent symptom, and osteoarthritic lesions are the main cause. The lesions begin in the sacroiliac joints and gradually involve the lumbar, thoracic and cervical vertebrae, resulting in blurring of the intervertebral joint space, loss of fusion, osteoporosis and destruction of the vertebral body, ossification of the ligaments, and even hunchback fixation and loss of work capacity. In addition to lumbar pain, it can be accompanied by stiffness and pain in the thoracic back and neck and joint pain in the lower limbs, with stiffness at rest for a long time and reduced or disappeared after activity; lumbar disc herniation has a relatively acute onset, commonly with a history of trauma, mostly in young adults, with lumbar pain accompanied by pain and numbness in the sciatic nerve distribution area, with increased pain with activity and no swelling in the joints of the lower limbs. On physical examination, ankylosing spondylolisthesis is not obvious or has only mild scattered pressure pain in the soft tissues of the lumbar region, and a variety of physical tests are negative, while the /40 word sign test may be positive. In the case of lumbar disc herniation, there is often obvious deep pressure pain next to the spinous process in the lower back or with radiating pain in the lower limbs, and neurological examinations such as straight leg raise test and strengthening test, thumb dorsal extension test, and flexion neck test are positive. Physical and laboratory examinations: X-ray examination shows blurred or narrowed sacroiliac joints in ankylosing spondylitis, elevated blood sedimentation when symptoms are obvious, and rheumatoid factor test is often positive, while lumbar intervertebral disc herniation has no such changes. The effect of treatment is different: lumbar disc herniation is often significantly improved after traction, manipulation, local closure and other systematic conservative treatment, while the effect of ankylosing spondylitis is not obvious after the above treatment. The diagnosis of ankylosing spondylitis is easier when the lumbar or dorsal neck and lower limb joint ankylosis is evident in the middle and late stages, and the X-ray is a bamboo-like change of the lumbar spine. 5, aseptic ischemic necrosis of femoral head The early symptoms of aseptic ischemic necrosis of femoral head are pain in the front, outside 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, and the 4-character sign test is positive, and the hip joint movement is limited in the middle and late stages. The diagnosis can be confirmed by further X-ray and MRI examination of both hips. Through careful consultation and physical examination, the differential diagnosis between aseptic ischemic necrosis of the femoral head and lumbar disc herniation is easier. 6.Sacroiliac joint dislocation Sacroiliac joint dislocation is a lumbosacral bone and joint injury that commonly causes sciatica in clinical practice. Both the misalignment and inflammatory reaction of sacroiliac joint can pull or stimulate sciatic nerve stem and pear-shaped muscle and cause pain or numbness in the affected limb, which is very similar to the symptoms of lumbar disc herniation, but there are still some differences. Sacroiliac joint misalignment commonly has symptoms that are sometimes mild and sometimes severe, with variable pain sites and blurred boundaries, and the affected limb feels shortened. The symptoms of lumbar disc herniation are more stable, and the area of pain and numbness is fixed. Signs:In sacroiliac joint misalignment, the lumbar spine scoliosis deformity protrudes to the healthy side, the pressure pain point is in the sacroiliac joint, and the 4-word sign test is positive. In the case of lumbar disc herniation, the lumbar scoliosis is more convex to the affected side, the pressure point is next to the spinous process of the lumbar spine, the spinous process is skewed or the upper and lower spinous gaps are not equal. x-ray and CT, MRI, etc. can help to differentiate. 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. The diagnosis can be made clearly by X-ray and MRI examination. 8, lumbar spinal stenosis Lumbar spinal stenosis is mostly seen in middle-aged and elderly people over 40 years old, with slow onset, different from central disc herniation which is often sudden. Its main symptoms are long-term lumbago, leg pain, intermittent claudication, and lumbago only manifests 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 raising test and strengthening test are positive. x-ray and MRI examination can help to identify the lumbar spine and the spinal canal. 9, the third lumbar transverse process syndrome, pear-shaped muscle injury syndrome The third lumbar transverse process syndrome and pear-shaped muscle injury syndrome is also one of the causes of lumbar numbness and leg pain. Third lumbar transverse process syndrome and pear-shaped muscle injury syndrome, there are obvious pressure points in the third lumbar transverse process or pear-shaped muscle site, early local soft tissue swelling, late local muscle relaxation or varying degrees of atrophy, local spastic nodules or striae can be palpated, third lumbar transverse process syndrome lower limb radiating pain generally does not exceed the nest; pear-shaped muscle injury in straight leg elevation 30b ~ 60b can cause increased pain, more than 60b after the pain is reduced. The pain is relieved instead after exceeding 60b. In lumbar disc herniation, the pressure point is next to the spinous process of the lower lumbar vertebrae, and there may be radiating pain in the lower extremities; the former is mostly negative in the former neurological examination of the lower extremities, and the latter is mostly positive. Since the gluteal epicutaneous nerve originates from the lateral branch of thoracic 12 to lumbar 3 and crosses the iliac spine through the back extensor muscle to the buttocks, the treatment of the third lumbar transverse herniation syndrome and pear-shaped muscle injury can be achieved with immediate effect by dividing the tendons and tendons with manipulation of the gluteal epicutaneous nerve and pear-shaped muscle pressure pain points.