The conus medullaris (bottom of the spinal cord) terminates at the level of L1 in adults, but may range in term neonates (newly born babies) from L1-L3 levels. It is important to insert the spinal needle below the conus medullaris at the L3/L4 or L4/L5 interspinous levels.Click to see full answer. In this manner, why is a lumbar puncture done between l3 and l4?A lumbar puncture (spinal tap) is the insertion of a needle between the lamina of the vertebrae and into the thecal sac with the purpose of obtaining cerebrospinal fluid. This is done below the L2 level (usually between L3-4 or L4-5) in order not to injure the spinal cord.Likewise, how is a lumbar puncture procedure done? Spinal tap (lumbar puncture) During a lumbar puncture (spinal tap) procedure, you typically lie on your side with your knees drawn up to your chest. Then a needle is inserted into your spinal canal — in your lower back — to collect cerebrospinal fluid for testing. Subsequently, question is, how painful is a lumbar puncture? Lumbar puncture. A lumbar puncture is where a thin needle is inserted between the bones in your lower spine. It shouldn’t be painful, but you may have a headache and some back pain for a few days. It’s carried out in hospital by a doctor or specialist nurse.How much CSF is taken in a lumbar puncture?Large Volume Lumbar Puncture. A large volume lumbar puncture is a special kind of lumbar puncture (spinal tap) specifically intended to remove 30 to 40 ml of cerebrospinal fluid (CSF) to both assess and temporarily relieve symptoms of hydrocephalus.