Introduction
CSF study is essential to diagnosing many CNS diseases from infections, inflammatory to malignancy. It is a widely accepted, relatively safe and routinely performed procedure.1In this Review, we summarise the essential CSF flow dynamics, common indications for lumbar puncture, describe the contraindications, and procedures to rule out these contraindications. We propose a checklist before LP, describe trends over the past two decades, the feasibility of outpatient LP and the complications of LP. We will also address some long-standing myths on LP and propose a flow chart to approach cases of difficult and failed LPs.