Question

While doing lumbar puncture, last structure to be encountered will be in a patient who presented with fever, neck rigidity & altered sensorium

• A. Arachnoid membrane
• B. Ligamentum flavum
• C. Dura mate
• D. Pia mater

Answer 1

The Correct Option is A

The lumbar puncture, also known as a spinal tap, is a procedure that involves inserting a needle into the subarachnoid space of the lumbar region of the spinal column to collect cerebrospinal fluid (CSF). This procedure is used for diagnostic purposes such as analyzing CSF in conditions like meningitis, evidenced by symptoms such as fever, neck rigidity, and altered sensorium.

During lumbar puncture, the needle passes through several anatomical structures in the following sequence:

1. Skin
2. Subcutaneous tissue
3. Supraspinous ligament
4. Interspinous ligament
5. Ligamentum flavum
6. Epidural space (containing internal vertebral venous plexus)
7. Dura mater
8. Arachnoid membrane

The arachnoid membrane is the last structure the needle passes before reaching the subarachnoid space where the CSF is located. Therefore, the correct answer is Arachnoid membrane.