To administer spinal anaesthesia. The patient is placed on his side at the edge of the bed with the knee drawn up towards abdomen and the head is flexed. It can also be done with the patient sitting and bending forward. The skin over the back from the lower thoracic vertebrae to the coccyx is sterilised with cetavlon, ether, iodine and spirit. The part is draped.
Infiltration is done up to the ligamentum flavum.
A Lumbar puncture needle with a stillete is introduced after 2-3 minutes in to the anesthetised space, with the cutting edge of the bevel in the direction paralllel to the fibres of the ligamentum flavum. The interspinous ligament is then easily negotiated. A give away sensation is felt as you breach the dura. The stillette is then withdrawn and the fluid is then collected slowly in 4-5 bulbs for biochemical, cytological and serological tests. The needle is then withdrawn and the puncture mark is sealed with at tincture benzoin seal.