Lumbar Puncture

INTRODUCTION

• Lumbar puncture and analysis of cerebrospinal fluid is widely used as a diagnostic tool in neurological diseases.
• Lumbar puncture (LP) is the insertion of a needle into the subarachnoid space in the lumbar region to obtain cerebrospinal fluid (CSF) for diagnostic or therapeutic purposes.
• The CSF obtained by LP can provide crucial data in the diagnosis of life threatening conditions such as meningitis and encephalitis and evaluation of other disease conditions such as demyelinating diseases.
• Lumbar puncture is alsoperformed for therapeutic reasons, such as the treatment of benign intracranial hypertension. 
•  The spinal cord ends at the lower border of L1 vertebrae (Fig 1).
• Below this are nerve roots – the cauda equina. Lumbar puncture can be safely done below L1-2 vertebral space, as there is no risk of injuring the spinal cord.