At what angle and direction is the needle inserted during a lumbar puncture (LP)?
you can tilt the needle at 45 as you go above the vertebral body then advance at 90
Using the index finger, stabilize the spinal needle and insert it into the skin using the thumb at a slightly cephalad angle directing it towards the umbilicus. The bevel of the needle is oriented parallel to the longitudinal dural fibers to separate the fibers instead of cutting. The bevel should be facing up in the lateral recumbent position and left or right in the sitting position. The needle is pushed in slowly and smoothly. A ‘pop’ is heard when it enters the lumber cistern where the ligamnetum flavum is attached. A second pop is felt when the needle penetrates the dura mater and the arachnoid membrane, as the arachnoid membrane is in close contact with the dura due to the pressure of the CSF. The needle is then in the subarachnoid space and the stylet is removed from the needle and drops of CSF fluid are collected. If drops are not collected, the stylet should be withdrawn after 4-5 cm and observed for fluid return. If no fluid is returned, change the stylet, move the needle forward or backward a few millimeters, and check for fluid return again. Carry on in this manner until the fluid has been effectively returned.
