Lumbar puncture is generally used in the middle of the spine, the 4th lumbar and 5th lumbar intervertebral space as the entry point, or the 3rd lumbar to 4th lumbar intervertebral space can also be used. The patient is instructed to lie on the side of the hospital bed, with the head held in the head position with the knees bent and the pillows removed. The middle part of the line connecting the highest points of the hip bones on both sides is usually the 4th.5 lumbar vertebral space. The last vertebral space is the 3rd. and 4th. vertebral spaces. 4th to 5th vertebral interspace, and the needle is tilted slightly upward during lumbar puncture. The needle can be inserted vertically when entering the 3rd to 4th lumbar vertebral interspace.