QS Study

Lumbar puncture:

It is a procedure in which a lumbar puncture needle is introduced between L3, L4 vertebra to reach the subarachnoid space for a collection of cerebrospinal fluid (CSF) or induction of intrathecal drugs for various diagnostic or therapeutic purposes. It also may be used to deliver an injection of chemotherapy or other medication into the lower spinal canal.

During a lumbar puncture, a needle is inserted between two lumbar bones to remove a sample of cerebrospinal fluid. This is the fluid that surrounds your brain and spinal cord to protect them from injury.

Indications –

(A) Diagnostic:

  1. For a collection of CSF for study.
  2. Myelogram: Dye injected in subarachnoid space to detect any obstruction.

 (B) Therapeutic: Intrathecal drugs –

  1. Methotrexate.
  2. Spinal anaesthesia.


Between L3 & L4 where an imaginary line joining the highest points on the iliac crests passes over the fourth lumbar spine. It is where a thin needle is inserted between the bones in your lower spine.

Procedure –

  1. A patient is kept lying on the side with the vertebral column well flexed.
  2. With a careful aseptic technique and under L/A, the lumbar puncture needle fitted with a stylet is passed in the vertebral canal at the level between L3, L4.

It can help diagnose serious infections, such as meningitis; other disorders of the central nervous system, such as Guillain-Barre syndrome and multiple sclerosis; or cancers of the brain or spinal cord.

Lumbar Puncture 1


  1. Local pain, haemorrhage
  2. Post L/P headache,
  3. Introduction of infection.
  4. Tonsillar herniation (compression of medulla)


  1. Raised intra cranial pressure
  2. Local infection
  3. Intracranial space occupying lesion
  4. Platelet < 40,000/mm.
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