No matter which minimally invasive surgery is carried out, familiarity with the anatomy of the lumbar spine and surrounding nerves and blood vessels is the most basic prerequisite for carrying out the surgery, followed by the accuracy of puncture and positioning. Minimally invasive surgery is influenced by the surgical incision and field of vision, and deviation in puncture positioning will directly lead to the inability to reveal the protruding disc after the working channel is established, as the saying goes. The orthopedic and neurosurgical surgeons can immediately take more alternate surgical remedies in case of failure of minimally invasive surgery. After the working channel is established and the spinal endoscope is implanted, the differentiation of the tissue under the mirror will be of paramount importance, and there is also a skilled process of the surgeon’s hand during surgery. The above are some of the basic key points for mastering the surgery. I. Composition of the intervertebral disc There are five intervertebral discs in the lumbar region, namely L1~2, L2~3, L3~4, L4~5, L5~S1. The intervertebral disc is composed of the annulus fibrosus, nucleus pulposus, hyaline cartilage endplates and sharpey fibers. The fibers are surrounded by tough fibrous tissue. The outer layer is mainly type I collagen fibers, which are densely arranged, with some collagen fibers inserted into the vertebral body; the inner layer is mainly lower density type II collagen fibers, which lack a distinct plate arrangement compared to the outer layer. The nucleus pulposus is located slightly posterior to the center of the disc in the lumbar region and has a translucent gel-like appearance in young cadavers, consisting mainly of cartilage matrix and collagen fibers, attached to the epiphyseal ring of the vertebral body by Sharpey fibers. The hyaline cartilage endplates are the superior and inferior cartilage surfaces of the vertebral body and form the superior and inferior boundaries of the vertebral body, separated from the adjacent vertebral body. sharpey fibers surround the outermost layer of the intervertebral disc, consisting mainly of collagen fibers without cartilage matrix. The disc stabilizes the spine and maintains its alignment by anchoring adjacent vertebrae, allowing reciprocal motion between vertebrae, and absorbing loads and energy loaded onto the spine. The lumbar intervertebral discs are in close contact with their surrounding tissues such as the spinal nerves, and disc herniation or degeneration can cause pathological changes in the surrounding tissues secondary to low back pain. In early childhood, the structure of the nucleus pulposus can be clearly separated from the annulus fibrosus, but in old age, the demarcation between the two is not obvious because the disc fibers become thicker. The density of the nucleus pulposus varies at different ages, and the density increases with age. During fetal life, the blood vessels of the intervertebral disc come from the surrounding tissues and the vertebral body, which passes through the cartilage plate to the deep part of the fibrous ring; after birth, the blood vessels are gradually atretched and completely atretched around the age of 12. In adults, except for the periphery of the fibrous ring, no blood vessels exist in other parts, and the nutrition of the nucleus pulposus and fibrous ring is supplied by infiltration of the peripheral tissues. Second, the anatomical characteristics of the intervertebral disc sagittal section of the lumbar intervertebral disc, the central expansion, the front and rear ends are larger, slightly inside a narrowing, the whole like a transverse vase, both sides such as the mouth of the bottle, the bottom and its neck. The thickness of the cartilage endplate section of the upper and lower vertebral body of the same disc was not significantly different at the left and right sagittal anterior, middle and posterior points. The thickness of the cartilage plates of the upper and lower vertebral bodies differed slightly between the different planes of the disc, with L1~2 being thinner, L4~5 being thicker, and L5~S1 being slightly thinner than L4~5 again. There are significant differences in disc area between genders: male disc area is larger than female, lower lumbar disc area L3~4 is slightly larger than L4~5, and L4~5 is slightly larger than L5~S1. The ratio of disc to adjacent lumbar vertebral body height is 0.3~0.6 in adults. the posterior edge of lumbosacral disc is normally straight or mildly retroverted. There is abundant epidural fat between the posterior edge of the lumbosacral disc and the front of the dural sac, which is helpful in the interpretation of CT images, and clearly developed epidural veins are usually seen within these fat layers. III. Vessels and nerves of the intervertebral disc The adult intervertebral disc is almost devoid of blood vessels, with only small vessels from segmental arterial branches penetrating around the annulus fibrosus, mostly at the anterior and posterior edges of the disc. In the fetus and early childhood, each disc is supplied by three arteries. The nerve distribution of the disc is similar to that of the blood vessels, with abundant nerve endings in the periphery of the annulus fibrosus and no nerve fibers in the deep parts, cartilage plates, or nucleus pulposus. The anterior and lateral parts mainly receive fibers from the sinus nerve. The sinus vertebral nerve mostly originates from the posterior branch of the spinal nerve, but it may also originate from the common trunk, which receives small branches of the sympathetic nerve and returns to the spinal canal via the intervertebral foramen, hence the name of the retrolateral nerve. The sinus vertebral nerve is first attached to the back of the intervertebral disc, and its ascending and descending branches travel up and down along both sides of the posterior longitudinal ligament, spanning two intervertebral discs each and a total of four vertebral bodies, and its transverse branches may anastomose with the opposite side. The sinus nerve is distributed in the structures of the spinal canal, and histologically, its sensory nerve endings have the highest density in the posterior longitudinal ligament, the anterior part of the dura mater, the nerve root sleeve, and the venous wall of the anterior venous plexus in the spinal canal, followed by the vertebral periosteum and the lateral part of the dura mater, and the posterior part of the dural sac and the ligamentum flavum are the rarest. This structure may explain the severe pain caused by stenosis of the lateral saphenous fossa and compression by herniated lumbar discs. Fourth, the lumbar intervertebral disc puncture access anatomical points 1, L4 ~ 5 disc adjacent to the L4 ~ 5 disc in front of the left for the abdominal aorta, in front of the right for the inferior vena cava, the left and right sympathetic trunk is located between the disc and the abdominal aorta, inferior vena cava, on both sides of the lumbaris major muscle and its fascia, retroperitoneum and abdominal organs, the lumbar plexus is located in the deep lumbaris major muscle, the front of the transverse process, the lumbar plexus and transverse process interval with a small number of muscle fibers. 2, L5 ~ S1 intervertebral disc adjacent to L5 ~ S1, the disc is thick in front and thin in the back, the front septum and abdominal organs adjacent to the iliopsoas muscle, L5 nerve roots, the common iliac vein on both sides. l5 nerve roots from L5 ~ S1 intervertebral foramen after walking in the arch-shaped tunnel formed between the transverse process of the 5th lumbar vertebra, the iliolumbar ligament and the sacral wing. Most of the lumbar 5 root arteries are branches of the iliolumbar artery, and a few emanate directly from the common or external iliac artery into the intervertebral foramen, where the root veins converge into the iliolumbar or common iliac veins. In this arch-shaped tunnel, the nerve roots reside medially and the vessels are lateral. He divided the L5-S1 intervertebral disc puncture zone into anterior, lateral and posterior lateral zones. The anterior zone has a wide gap and large area, which is safe for puncture. The disadvantage is that it needs to pass through the abdominal cavity, and the operation should be guided by laparoscopy. The lateral zone has a 40% chance of puncturing a nerve or vessel due to the difference in the location of peripheral nerves and vessels, as well as the high rate of the iliolumbar vein or its branches, and the unpredictable location and travel, and the risk of hemorrhage if the common iliac vein or the main stem of the iliolumbar vein is punctured. When the puncture angle is greater than 90 degrees, the puncture needle may injure the appendix. The postero-lateral puncture route is shallow, and it is easy to operate without drilling holes in the iliac bone when using straight needle puncture, and it does not pass through the abdominal cavity, so the lateral posterior approach is preferred for the L5-S1 intervertebral disc. V. vertebral body The lumbar vertebral body has 5 blocks, because of the greater weight bearing, so the vertebral body volume is large, is kidney row, the transverse diameter is greater than the sagittal diameter; and because of the occurrence of lumbar curvature, the height of the anterior and posterior edges of the comparison is low, only 0.88. But from the lumbar 1 below the gradual increase, lumbar 5 maximum, up to 1.17, men and women are basically the same. The arch of the lumbar spine extends outward to the posterior, the upper vertebral notch is smaller, and the sagittal diameter sequence decreases from lumbar 1 downward, while the lower vertebral notch is larger. There is little difference between upper and lower. The arch plate is thicker and slopes slightly downward and backward. The vertebral foramen is triangular and small. The upper articular processes of the lumbar vertebrae emanate from the arch root and meet inwardly with the lower articular processes of the previous lumbar vertebrae, and the intervertebral joints are oriented in a sagittal position but gradually become oblique downward. The intertransverse synapse is called the narrow part. The transverse process of the third lumbar vertebra is the longest, and the muscles attached to it can produce avulsion fractures if they contract strongly. The spinous process of the lumbar spine is plate-like and extends horizontally to the posterior. Sixth, the synovial joint 1, structure The synovial joint, also known as the intervertebral joint or small joint, is a joint formed by the upper and lower synovial processes of adjacent vertebrae, and is a synovial joint, which allows a certain range of activities between the two vertebrae. Disruption of the intervertebral joint in the lumbar region can cause lumbar instability and low back pain. Hyperplasia of this joint can cause the intervertebral foramen to become relatively small and compress the spinal nerve. During fetal and infant periods, the articular surface of the lumbar synovial joint is nearly coronal, and later, as the lateral edge of the synovial joint gradually grows in the sagittal direction, the articular surface becomes curved and predominantly sagittal. The articular surfaces of the superior lumbar synapses are sagittal, while the inferior ones are coronal, especially in the 5th lumbar vertebra. The joint tilt of the articular processes of the lumbar spine is highly variable and often asymmetric on both sides. The articular surface of the superior articular eminence of the 5th lumbar vertebra is mostly concave, and a few are planar; the articular surface of the inferior articular eminence is also highly variable, with convex and planar shapes predominating, followed by concave and wavy (S-shaped). The articular surface of the articular eminence is covered with a layer of cartilage, which thins with age, and the bone in the lower part of the articular surface becomes irregular, hyperplastic and hardened. 2, blood vessels and nerves of the synovial joints are supplied by the lumbar artery, which travels to the vertebral arch near the isthmus and penetrates the vertebral plate to send branches to the upper and lower synovial joints. The corresponding veins of the superior and inferior synapses then merge with the external vertebral veins to form the vertebral arch veins, which are injected into the intravertebral or lamina venous plexus at the intervertebral foramen. The innervation of the lumbar synovial joint comes from the medial branch of the posterior branch of the lumbar nerve, which passes backward through a bone fiber canal and is distributed to the intervertebral joint and its surrounding structures. The first bend of the “S” shape. (2) Inner segment of the osteofibular canal: located in the osteofibular canal, forming the middle turn of the “S”-shaped stroke. The posterior segment of the osteofibular canal: from the outlet of the osteofibular canal to the nerve is divided into the terminal muscle branch, which constitutes the second bend of the “S” segment and divides into the first articular branch, spinal branch, second articular branch, spinal branch and third articular branch in turn. The stroke of the posterior medial branch of the lumbar nerve is roughly “S”-shaped, and this structure greatly increases its ability to stretch and cushion the nerve from strain during movement to avoid injury. The lumbar synovial joints are innervated by the anterior and posterior branches of the anterior and posterior branches of the nerve trunk in the same or superior position, and there is a rich segmental anastomosis, which is multi-source and bi-segmental in distribution. In terms of the travel of the posterior lateral branch of the lumbar nerve, there are the following vulnerability factors: ① The edges of the bony fiber canal entrance are in close proximity to the posterior medial side. (2) The “S”-shaped turn of the bony fiber canal is the narrowest. (iii) Narrowing of the ossification of the inferior segmental canal. (iv) The nerves pass through the osteofibular canal like a rope sliding and rubbing in the narrow and curved canal. Therefore, when there is inflammation or other lesions in the osteofibular canal and its surrounding structures, it is easy to cause nerve injury and secondary back pain. Since an intervertebral joint lesion can involve several segments of the lumbar nerve, the localization of low back pain is less clear. 3, joint capsule The joint capsule of the articular eminence is mainly located in the posterior lateral part of the articular eminence, while the anterior medial joint capsule is mostly replaced by the ligamentum flavum. The innermost layer of the joint capsule is the synovial membrane, and the synovial tissue protrudes into the joint space to form folds. The intervertebral joint capsule is tense and has a certain degree of mobility. The capsule is attached by the multifidus muscle outside and connected to the ligamentum flavum medially. The joint capsule is divided into a fibrous layer and a synovial layer. The synovial layer is smooth and translucent, and it is not easily separated from the inner surface of the fibrous layer. About 1/3 of the synovial layer starts from the edge of the articular cartilage and is connected by connective tissue between the beginning of the synovial membrane and the edge of the articular cartilage, and the joint cavity is narrow and closed. The synovial layer protrudes bilaterally between the adjacent articular surfaces to form synovial folds that extend into the joint cavity. Synovial folds occur in 90% of the joints and are divided into two categories according to their histology: synovial fatty type and fibrocartilaginous type. There are four types of synovial folds according to the relationship between the root of the synovial fold and the edge of the joint surface, namely the upper, lower, inner and outer edges. Type I: synovial folds appear only on one side of the joint; Type II: synovial folds appear on both sides of the margin, such as the superior and inferior lateral margins; Type III: synovial folds appear on three sides of the root, such as the anterior, posterior, and lateral margins; Type IV: synovial folds appear on four (full) sides of the root. The physiological function of synovial folds: filling the cushion role, cushion between two adjacent joint surfaces, or joint cartilage table two fossa, so that the joint surface flat and smooth conducive to joint sliding; synovial layer and synovial folds can produce and absorb synovial fluid, lubrication and nutrition of the joint. If the synovial folds are squeezed between the adjacent articular surfaces, severe pain can result, which is called synovial impingement syndrome. Under normal circumstances, there are longitudinal multifidus muscle attachments on the top, back and outside of the joint capsule, and the multifidus muscle fibers of the corresponding segment contract during spinal movement, pulling the joint capsule to drive the synovial folds not to be embedded between the joint surfaces; if a patient with lumbar disc herniation or lumbar degeneration suddenly feels severe pain in the low back after strong or improper spinal movement, it may be due to inflammation, swelling or displacement of the synovial folds squeezed in the adjacent This may be due to inflammation, swelling, or displacement of synovial folds pressing on the adjacent articular surfaces. The outer fibrous tissue of the articular synovial capsule contains abundant nerve endings, of which mechanoreceptors in the form of myelinated fibers have low thresholds and are sensitive to stresses generated under normal physiological conditions; while another class of injury receptors in the form of unmyelinated C-fibers have higher thresholds and react only when they are subjected to stronger mechanical and chemical stimuli, and such receptors may be related to the process of occurrence of low back pain. The spinal canal is a fibrous canal enclosed by the intervertebral foramen of the free vertebrae and the sacral canal of the sacrum together with the connection between them. Its contents mainly include the spinal cord and cauda equina, spinal nerve roots, the dural sac, the epidural space and the connective tissue within it, and the intravertebral venous plexus, the subarachnoid space and the cerebrospinal fluid within it. The morphology of the lumbar spinal canal varies, with lumbar 1 and 2 being mostly ovoid, lumbar 3 and 4 being mostly triangular, and lumbar 5 being mostly trilobar. The normal measurement range for the anterior and posterior diameters is 15 to 25 mm. abnormalities of the bony and fibrous structures of the spinal canal occur for a variety of reasons, resulting in one or more spinal stenoses that compress the spinal cord, cauda equina, and nerve roots. In addition to intervertebral discs, structural protrusions into the spinal canal include ossification of the posterior longitudinal ligament, hypertrophy of the ligamentum flavum, thickening of the vertebral plate, osteophytes of the articular eminence, and osteophytes of the posterior border of the vertebral body. In turn, these changes are often secondary to disc degeneration or traumatic factors. The lumbar spinal nerve roots travel in the lateral saphenous fossa and the disc yellow wink gap of the lumbar spinal canal, and disc herniation, yellow ligament hypertrophy, and synovial joint degeneration and hyperplasia can all compress the lumbar spinal nerve roots and cause lumbar pain. Position has a certain influence on the volume of the spinal canal, the lumbar spine from the straight position to the forward flexion position, the volume of the intervertebral foramen increased by 3.5-6.0 ml; posterior extension position, due to the posterior wall shortening volume reduction, posterior protrusion of the intervertebral disc, the yellow ligament convexity, so that the pressure on the nerve root to be pressed increased. Therefore, it is easier to find pressure points in the lumbar region when pressing in the posterior extension position. The lumbar nerve channel refers to the narrower bony fibrous channel of the lumbar nerve from the time it leaves the dural sac until it leaves the foramen (canal) of the spine. Lesions in any part of this channel can produce lumbar pain. It is generally divided into two segments: the first segment, called the nerve root canal, penetrates from the dural sac to the internal mouth of the intervertebral canal. Although this segment is not long, there are several narrow gaps, i.e., the disc-yellow gap, lateral saphenous fossa, superior pars distalis and inferior arch root groove, which are abnormal structures that can compress the lumbar nerve roots; the second segment is the intervertebral canal (foramen). Lee divided the lumbar nerve channel into three zones, namely the entrance zone, the middle zone, and the exit zone. The entrance zone is the most cephalic part of the lateral part of the lumbar spinal canal, located medially or below the superior articular eminence, and this zone has only anterior and posterior walls, with open medial and lateral surfaces. The anterior wall is the back of the intervertebral disc, the posterior wall is the articular eminence, and the lumbar nerve roots reside in this zone, covered with dura and immersed in cerebrospinal fluid. Under normal conditions, this zone is short because the superior articular process is often located lateral to the nerve roots. In the pathological state, the medial edge of the superior articular eminence and the bony bulge on the superior edge of the arch plate cover the nerve roots, making this zone longer. The middle zone is located below the interarticular portion of the arch plate and below the arch root, with the anterior border behind the vertebral body and the posterior border of the interarticular portion of the arch plate, with the medial border opening into the central spinal canal. The nerve structures contained in this region are the spinal nerve roots and anterior roots, covered with fibrous connective tissue of the dura mater and immersed in cerebrospinal fluid. Compared to other parts of the lumbar nerve, the spinal ganglia are larger, have more space, and are more sensitive to stenosis. The exit zone is the area around the intervertebral foramen with the posterior border of the lateral aspect of the articular eminence joint and the anterior border of the intervertebral disc. Both the articular eminence and the intervertebral disc in this zone are below one level of the same lumbar nerve entrance zone. The lumbar nerve course of this zone is overlaid by the epineurium. The L4, L5, and S1 nerve root canals differ in that the more dislocated the nerve root canal is, the shorter the distance it travels, the closer it travels to the horizontal, and the lower the point of emanation. the L4 nerve root canal originates from the upper part of the lumbar 4 vertebral body and does not cross the intervertebral disc, but only crosses the A and B regions (bony channels). stenotic lesions between the L3 and 4 vertebrae mostly do not involve the L4 nerve The L5 nerve root canal is longer than L4, tends to travel more vertically than L4, and has a relatively higher emanation point, usually starting in the lower part of the L4-5 intervertebral disc, the lower part of the intervertebral disc, the D zone, or the lower part of the disc yellow space, and then entering the lumbar 5 lateral saphenous fossa and the L5-S1 intervertebral canal. The lumbar 5 nerve root consists of three parts: the disc yellow gap, the lumbar 5 lateral saphenous fossa and the L5~S1 intervertebral canal, i.e., via three zones. the S1 nerve root canal is the longest of the three, nearly vertical, and has the relatively highest emitting point, mostly starting at the upper edge of the L5~S1 disc, so the sacral 1 nerve root canal passes through zones C, D, A and B. The L5 nerve starts in zone D, the hinge zone, which is the main site of stenotic lesions. Lesions at this level often involve the beginning of the L5 nerve root and the interior of the dural sac of the S1 nerve root located within it. 2, lateral saphenous fossa The lateral saphenous fossa, or spinal nerve canal, is the lateral part of the spinal canal, with the posterior lateral border of the vertebral body in the anterior part, the superior articular eminence in front of the posterior wall with the ligamentum flavum, and the external arch root. In the lumbar segment, the two sides of the lumbar spinal canal on the disc is called the disc yellow gap, flat on the vertebral body is called the lateral saphenous fossa. The lateral fossa is continued downward in the intervertebral foramen, and the lumbar part is narrower. The 5th lumbar spinal canal is trilobar-shaped, the lateral saphenous fossa is especially obvious, the anterior and posterior diameter of the lateral saphenous fossa is usually 3~5mm; if it is less than 3mm, the lateral saphenous fossa can be considered narrow; if it is greater than 5mm, it is definitely not narrow. The disc-yellow gap can be narrowed by posterior protrusion of the disc, hypertrophy of the ligamentum flavum or coalescence of the articular eminence, when the compression is on the next, or even the next two, spinal nerve roots. Only in the L4~5 and L5~S1 discs can the epidural segment of the lower nerve root be compressed at the same time. Because the nerve roots of the same order do not enter the disc yellow gap, that is, they turn out of the intervertebral foramen, so they are not affected. It is common for herniated discs to compress nerve roots at L4~5 and L5~S1, the disc yellow gap, and the direction of compression is from the nerve roots medially, laterally or anteriorly to the posterior apex, but the latter is more common. The upper and lower boundaries of the intervertebral foramen are the arch roots, the bottom from top to bottom are the posterior inferior edge of the superior vertebral body, the intervertebral disc and the posterior superior edge of the inferior vertebral body, the top is composed of the yellow ligament, behind the yellow ligament is the articular eminence joint, and the size of the intervertebral disc foramen is related to the height of the intervertebral space. The intervertebral foramen is lined with nerve roots, arteries, and veins that pass through it. There is a fibrous septum in the lower part of the intervertebral foramen, which is connected between the fibrous ring of the intervertebral disc and the articular eminence joint, dividing the intervertebral foramen into upper and lower canals: the upper canal has nerve roots, the intravertebral branch of the lumbosacral artery and the upper branch of the intervertebral vein; the lower canal has the lower branch of the intervertebral vein. There is a fibrous septum in the upper part of the external orifice of the intervertebral foramen, which is connected to the intervertebral disc fibrous ring and the intertransverse ligament, dividing the external orifice into upper and lower orifices. In the high lumbar spine, the fibrous septum is higher and thinner; in the lower lumbar spine, it is low and thick, in the form of a diaphragm, which closes off most of the middle of the foramen. The fibrous septum, which serves to separate the spinal nerves from the blood vessels, protects the thinner intervertebral veins and does not compress the nerve roots. The presence of the fibrous septum may aggravate the compression of the nerve root in the presence of a posterolateral type of disc herniation, osteophyte or metastatic tumor. The nerve roots emanate obliquely outward from L1 to S1, and the angle between the nerve roots and the dural sac decreases from 40° to 22°. L3 to 4 nerve roots are located on the medial surface of the arch in the same order. L5 and S1 nerve roots descend through the lateral saphenous fossa, and only a few leave the dural sac and enter the intervertebral foramen first through the L4 to 5 disc yellow space. In the intervertebral foramen, the supratentorial ligament starts from the angle between the arch and the transverse process and ends at the lateral wall of the lateral vertebral body or intervertebral disc in the same position, with arterial and venous branches and sympathetic nerves passing through the interspace above the ligament; the inferior foraminal ligament crosses the supratentorial notch, starts at the bony surface of the anterior border of the superior articular process, travels horizontally forward and ends at the posterior lateral aspect of the vertebral body or intervertebral disc, with a venous branch passing through the intervertebral foramen from below. The nerve travels between the supratentorial ligament and the infratentorial ligament; the transverse corporal ligament is located outside the intervertebral foramen, starting from the transverse process and running obliquely forward and ending at the lateral wall of the vertebral body or disc; the transverse corporal ligament covers the intervertebral foramen and the nerve roots, which pass out of the foramen from below the transverse corporal ligament; outside the transverse corporal ligament, the extravertebral venous plexus and segmental arteries send out two to five branches intertwined with each other, and these vessels pass through the small foramina separated by the ligament These vessels pass through the intervertebral foramina or travel with the nerve roots. The course of the foraminal ligament is mostly horizontal or oblique and has little effect on the transverse foraminal meridians. The foraminal ligaments separate the arterial and venous branches from the neurological reports, and as the size of the foramen changes with spinal motion, the tension of the ligaments, which originate and terminate at different vertebral bodies, will change, and the nerve roots will not be compressed by these ligaments simply because of the kinematic narrowing of the foramen. Ligaments that originate and terminate in the same lumbar vertebra do not change in tension with foraminal motion, but the position of the ligaments changes with the relative motion between the upper and lower vertebral bodies, causing changes in the diameter of the nerve root exiting the foramen. The intervertebral foramen ligament has a limiting effect on the activity of the nerve root, but under normal circumstances, the diameter of the nerve root is significantly smaller than the diameter of the nerve root foramen, and the possibility of nerve root compression is small; the blood vessels and small nerve branches at the intervertebral foramen are protected by the ligament and will not be affected by the mutual movement between the foramen and the nerve root. After degeneration of the lumbar spine, morphological structural changes in the intervertebral disc, synovial joint, and ligamentum flavum can lead to changes in the morphology and position of the foraminal ligaments, and these changes can increase the risk of vascular and nerve root compression. Some authors have suggested that degeneration of the lumbar 5 intervertebral disc can cause inferior displacement of the transverse corporal ligament trapping the anterior branch of the L5 nerve causing lumbar and leg pain. In addition, inflammatory swelling, scar formation and hyperplastic calcification of the intervertebral foraminal ligament itself can also cause foraminal deformation and stenosis. Clinically, the pathological role of the intervertebral foraminal ligament should be considered in cases of middle-aged or older patients with low back and leg pain who have a positive straight leg raising test and whose CT and MRI show no significant protrusion of the intervertebral disc or poor results after nucleus pulposus removal. The cause of intervertebral stenosis can be developmental, when the vertebral arch is shortened and accompanied by narrowing of the lateral saphenous fossa, but most commonly it is a lesion of the intervertebral disc. After narrowing of the intervertebral space, the superior articular process moves up and forward, and due to abrasion and thus hypertrophy of the bone, the nerve roots behind it are pressed against the top. This occurs mainly in the supra-articular synapse of sacral 1, leading to the narrowing of the intervertebral canal from L5 to S1; in another case, the narrowing of the intervertebral space caused by degeneration of the nucleus pulposus, the relaxed fibers protrude posteriorly and jam the nerves of the same order in the groove between the fibrous ring and the subacromial notch (subacromial groove), causing the nerve roots to be twisted and compressed, which is mostly seen when the disc degeneration collapses asymmetrically on both sides. The collapse of the disc degeneration also leads to relaxation, hyperplasia and hypertrophy of the transverse ligament, which becomes an important factor in nerve root compression. The posterior branch of the lumbar spinal nerve is divided into anterior and posterior branches after the lumbar nerve exits the intervertebral canal, and the posterior branch and its branches pass through the bony fibrous canal at several points in its journey. The bony fibrous canal of the posterior branch of the lumbar nerve is located outside the intervertebral foramen and at the upper edge of the transverse process root. The bony surface of the anterior segment is the anterolateral aspect of the sacral and superior articular process root, and the superior lateral aspect is the fibrous membrane. The inner, upper, and outer walls of the posterior segment are within the sulcus formed by the supra-sacral articular process and sacral wing, and the upper wall is part of the iliolumbar ligament. The medial branch of the posterior lumbar nerve travels through the posterior lower part of the ipsilateral lumbosacral joint. after the degeneration of the L5-S1 disc, the inferior lumbar 5 articular eminence sinks and can squeeze this medial branch. When bending over, this medial branch rises slightly, and when the nerve is not able to retreat when extending the back, it will be compressed by the sinking inferior articular eminence, causing acute pain. The mechanism of posterior branch lumbago: when the posterior lumbar expenditure bone fiber hole, close to the intertransverse process ligament, adjacent to the transverse process, joint synapse, surrounded by only a little fatty tissue; in the transverse process is fixed on the transverse process by the fiber bundle, no obvious fatty tissue around, this section is relatively fixed section, is the anatomical basis of posterior branch lumbago, is also the biomechanical basis of nerve pulling injury. The posterior branch is strained when the lumbar spine is flexed forward, bent contralaterally, and rotated contralaterally, and the strain is gradually increased with the increase of the range of motion, which may be due to the tension of the ipsilateral intertransverse process ligament with the increase of the range of motion, and the strain on the posterior branch is gradually increased, so the strain on the posterior branch is increased. When bilateral asymmetry of the vertebral arch root, bilateral asymmetry of the small joint gap, and heavy shadowing of the posterior edge of the vertebral body appear on the lateral x-ray, the tension on the posterior branch increases with the obviousness of these signs, so the above x-positive finding is an objective reference basis for the diagnosis of posterior branch back pain. However, due to the complexity of low back pain, the diagnosis must be combined with clinical examination.