Physical examination. The “Three Clinical Tests of the Lumbar Spine” proposed and recommended by Mr. Hsuan has a distinct specificity for lesions within the lumbar spinal canal, and can accurately make a differential diagnosis with lumbar leg pain caused by damage to soft tissues outside the lumbar spinal canal. Lumbar disc herniation, lumbar spinal stenosis, inflammatory tissue reaction outside the nerve root and dural sac, and nerve tumors can all show common positive signs of the three tests. The test has both specificity and sensitivity in clinic, and the detection rate is quite high. 1, chest, abdominal pillow test clinical significance (1) chest pillow test is positive, suggesting lumbar spinal canal lesions. (2) Abdominal pillow test is positive, can be considered as soft tissue damage outside the spinal canal lumbago. 2, lumbar scoliosis test clinical significance (1) ① spinal curvature to the affected side triggered deep pain in the lumbosacral region or concomitant radiating pain in the buttocks and lower extremities or soreness, it is a positive sign, can be judged to have intradural pathogenesis. (2) When the spine bends to the healthy side to the extreme, the deep lumbosacral pain and lower extremity signs induced by the original scoliosis test on the affected side disappear completely, also indicating that the test is positive. (2) If the spine curves to the healthy side and there is pain in the lumbar region on the affected side, it can be judged as soft tissue damage outside the lumbar spinal canal. (3) If pain in the lumbar or lumbosacral region is induced when the spine bends to the affected side or the healthy side, it will be judged as lumbar pain caused by mixed lesions inside and outside the lumbar spinal canal. Clinical significance of tibial nerve flick test Anyone who flicks the tibial nerve trunk during examination and experiences localized pain or conductive soreness and numbness in the calf is positive for this test. If the finger presses the nerve trunk or the joint capsule at the back of the knee, false positive signs can be induced. (C) Imaging features 1. X-ray plain film. The following changes are used as reference. (1) Interdiscal changes. (2) Frontal and lateral intervertebral sequence/curve changes. Lumbar spinal canal lesions (lumbar disc herniation) can occur lumbar scoliosis and lumbar spinal kyphosis, in the case of severe damage to the soft tissues of the lumbar or buttock region can likewise occur, and clinically often manifests itself as a severe mixed lumbar intra- and extra-vertebral canal lesion. 2.CT scan or MRI examination. Measurement of the size of the spinal canal, i.e. the presence or absence of stenosis (central spinal canal, lateral spinal canal, intervertebral foramina) and structural and morphologic changes in the contents can be used as a hint. The shape, size, location, segmental range and relationship with the dural sac and nerve root of the herniated disc can be more clearly diagnosed. The detection rate of vertebral canal tumor is also very high, which has important reference value. (iv) Electromyography. It can be distinguished into neurogenic damage and myogenic damage, both of which indicate that they come from intravertebral canal disease. 1, Nerve root involvement. If a large number of fibrillation potentials and positive-phase potentials are found in the tibialis anterior muscle (L.4, 5) and peroneus longus muscle (L.5, S.1), and at the same time the action potentials are reduced without significant changes in the wave amplitude and wave width, then it indicates that the L.5 and spinal nerves may be involved. If the loss of innervation potentials is also detected in the sacrospinal muscle innervated by L.5, the involvement of the L.5 nerve root segment can be determined. If no abnormal potentials are found in the sacrospinal muscles innervated by L.5, a peripheral lesion should be considered. The localization of radicular pain in most limbs can be determined on this basis. If a large number of loss of nerve spontaneous potentials are detected in atrophic muscle groups, along with a decrease in motor units, while the conduction velocity is normal and the amplitude and width of action potentials are high, it indicates the possibility of spinal cord lesions. 2. Myogenic damage. Action potentials are also not reduced and the wave amplitude is lower, the width is narrower, the nerve conduction velocity is normal, then most belong to myelopathy. Simple shortening of the average time limit of action potentials indicates that the muscle tissue is dysfunctional due to the influence of aseptic inflammatory stimulation of the nerve roots. II. Determining the site (I) lesions in the lumbar spinal canal 1. Anterior flexion and posterior extension functional activities of the lumbar spine. The lumbar forward flexion activity is firstly accomplished 50% by hip flexion, and secondly really 50% by the lumbar spine itself. About 75% of the lumbar anterior flexion activity is mainly dependent on the function between L.5-S.1 (the remaining 25% of the function is accomplished by L2-5). When there is a herniated disc at L.5-S.1 or damage to the lumbosacral or sacrospinal muscles it will significantly limit forward flexion activities. In contrast, lumbar posterior extension activities are mainly accomplished by lumbar vertebrae 2-5 segments for posterior extension activities. The above conditions make the L.5-S.1 segments less affected, thus limitation of lumbar posterior extension activities with neurological symptoms should be considered for L.3-4/L.4-5 segment lesions. Similarly, the motion segment that affects sitting work should be the L.5-S.1 segment. 2, lumbar spine paraspinous or median area of pressure pain, can suggest that the spinal canal segmental damage. The interspinous pressure pain with interlaminar pressure and radiating pain in the lower limbs beside the spinous process indicates a centralized lateral herniation of the intervertebral disc; if there is only interspinous pressure pain or interlaminar pressure beside the spinous process and radiating pain in the lower limbs, then it should be considered as a centralized or lateral type of herniation of the intervertebral disc. Of course, the location of the pressure pain is of great value in distinguishing the damage of different segments of the spine, especially the spinous process percussion pain is very meaningful in the detection of intravertebral space-occupying lesions, which can be used as a screening method before CT scan/MRI examination. 3.Neurologic localization signs. High diagnostic value, but late clinical manifestation. (1) Sensory loss or disappearance. The distribution of sensory nerves in the lumbar back is mainly innervated by the posterior branch of the spinal nerve; the distribution of sensory fibers in the vertebral canal is innervated by the vertebral sinus nerves issued by its posterior branch, and the limbs are innervated by the sensory branches issued by the plexus composed of the anterior branch of the spinal nerve. Therefore, the sensory impairment in the dermatomal area corresponding to the innervation of the affected nerve root can be used as a reference for the diagnosis and localization of lumbar spinal canal lesions. However, the premise is to first distinguish the two kinds of lesions inside and outside the spinal canal. When the sciatic nerve trunk and its branches are compressed by spasm or degenerative contracture of the soft tissues in the lumbar and buttock regions, the sensory loss or loss of sensation in the dermatomal area innervated by the nerve root of the lumbar region is the same as that of the lumbar nerve root itself. Sciatica and hyperalgesia or hyperalgesia of the lateral calf are common signs of both internal and external damage to the spinal canal. (1) Lateral thigh dermatomal area. It comes from the nerve branches of the lumbar plexus (L.2, 3). ② Anteromedial cortical area of the anterior calf. Nerve branches from the lumbar plexus (L.4). (iii) Posterolateral thigh, lateral calf cortical area, lateral ankle, dorsum and medial three toe cortical areas. From the sacral plexus (L.5-S.1) nerve branches. (iv) The posterior thigh, posterior calf, plantar or lateral margin of the foot, and the lateral two pedicled dermatomes. From the sacral plexus (L.5-S.1, 2) nerve branches. (2) Muscle weakness. Weakness of muscle strength in different parts of the body reflects the affected ganglion. Such as quadriceps muscle weakness reflecting L.2, 3, 4 segmental involvement (knee extension ↓); tibialis anterior muscle muscle weakness reflecting L.4 segmental involvement (dorsiflexion ↓); extensor hallucis longus muscle weakness reflecting L.5 segmental involvement (bunion extension ↓); plantarflexion and flexor digitorum profundus muscle muscle weakness reflecting S.1 segmental involvement (plantar flexion of the toes ↓); but it must be noted that the muscle strength is also weak or atrophy is also a common sign of the internal and external lesions in the spinal canal. Clinically, single-footed support of the torso movement (jinqi standing) can indicate S.1 ganglion involvement or not. (3) Reflex disorder. The tendon reflexes of the lower limbs have more accurate localization significance. In intravertebral lesions, it can identify the affected ganglion. Decreased or absent knee tendon reflexes reflect lesions in L.3 and 4 segments. Decreased or absent Achilles tendon reflexes reflect lesions in the S.1 segment. If there are pathological reflexes such as Babinski’s sign, we should consider the intravertebral canal lesion to the vertebral body bundle sign in the cervicothoracic spine, which is mostly caused by spinal cord damaging lesions. 4, prone position flexion and hip extension test, L.4-5 disc herniation stimulation compression of the L.5 nerve root, this test can be positive. However, if the L.5-S.1 disc herniation stimulates and compresses the S.1 nerve root, this test will not induce radiating pain in the lower limbs, so it can identify the nerve damage in the L.4-5 and L.5-S1 segments. (II) Soft tissue damage outside the lumbar spinal canal 1. Pressure points and referred pain (1) Pressure points in the lumbar gluteal region. Pressure point of superior gluteal cutaneous nerve; pressure point at the inferior outlet of sciatic nerve pyriformis muscle; pressure point at the superior outlet of superior gluteal nerve pyriformis muscle; pressure point at the inferior outlet of inferior gluteal nerve pyriformis muscle; pressure point at the slapping fossa of tibial nerve; pressure point at the inferior inferior inferior inferior inferior inferior inferior inferior inferior inferior inferior adipose cushion; pressure point under the medial ankle (tendon of posterior tibial tendon and tendon sheath); pressure point under the lateral ankle (tendon of peroneus longus and shortus tendon and tendon sheath). (2) Drawing pain. Soft tissue damage to the area innervated by the spinal sinus nerve or the posterior branch of the spinal nerve can produce radiating pain in the lower extremities similar to spinal nerve root involvement. Usually the pathway of the radiating pain is vague and not necessarily very far, and in a few cases it can reach the end of the limb. 2. Functional examination. It can confirm the pressure point and help to localize the pain. (1) Straight leg raising test: sciatic nerve tension; (2) Flexed knee and hip split leg test: adductor muscle group; (3) Hip abduction test: gluteus medius; (4) Iliotibial bundle tension test; (5) Hip internal rotation test: pyriformis muscle; (6) Sacroiliac joint test: “4” test, gonadalgia test, Avery’s test; (7) Bin fat pad squeeze sign; (8) Mai’s test: meniscus; (9) Drawer test: cruciate ligament of the knee; (10) Femoral nerve tension test. Third, distinguish the nature. The nature of the lesion can be clarified based on clinical features, imaging and laboratory diagnosis. (I) Intravertebral canal disorders 1. Tumor or specific lesion (1) Tumor: neurofibroma, nerve sheath tumor, nerve root cyst, dermoid cyst, ventricular meningioma, metastatic carcinoma (liver, kidney, prostate, ovary), glioblastoma of the spinal cord, neuroblastoma, and arteriovenous tumors. (2) Malformations (sacralization, lumbarization, spina bifida). (3) Spinal cord cavernous disease, multiple sclerosis. 2. Common disorders. (1) Lumbar disc herniation (central, lateral paracentral, lateral, extreme lateral, anterior). (2) Thoracolumbar spinal stenosis (congenital, developmental, degenerative, traumatic, medical, mixed). (3) Lumbar spondylolisthesis (leading to secondary spinal stenosis). (4) Soft tissue damage (hypertrophy of ligamentum flavum, calcification of posterior longitudinal ligament, degenerative contracture of fatty connective tissue, etc.). (ii) Extra-vertebral canal lesions. 1. Tumor or specific lesion (1) Spinal tumor, tuberculosis, eosinophilic granuloma. (2) Sequelae of spinal injury: compression fracture, cleavage fracture, fracture dislocation. (2) Rheumatoid arthropathy. Rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, Lister’s syndrome, systemic lupus erythematosus, gouty arthritis, dermatomyositis and reactive arthritis, sacroiliac joint disorders, ischemic necrosis of the femoral head. 3.Organ diseases and systemic diseases. Hepatobiliary and digestive system, genitourinary disorders, gynecological disorders, endocrine disorders (hypothyroidism, diabetes, aldosteronism). 4, vascular diseases. Thromboembolic vasculitis, thrombophlebitis, common iliac artery or external iliac artery thrombosis. 5, soft tissue damage (including myofascial pain syndrome, fibromyalgia syndrome). Roughly divided into the lumbar muscle group, gluteal muscle group, internal retractor femoris muscle group, lateral abdominal muscle group, slap cord muscle group, medial and lateral head of gastrocnemius muscle, infrapatellar fat pad, peroneus longus shortus, posterior tibialis muscle group, soft tissues of tarsal sinus, and metatarsal tendon membrane, etc., the damaging aseptic inflammatory reaction. 6, Infectious. Herpes zoster, lymphangitis.