During a lumbar puncture procedure, the spinal needle traverses several anatomical layers in a defined sequence before reaching the subarachnoid space. Given the structures listed below, which option correctly represents the order in which they are pierced? 1. Ligamentum flavum 2. Supraspinous ligament 3. Interspinous ligament 4. Dura mater 5. Subdural space 6. Arachnoid mater 7. Epidural space Which option correctly represents the order in which they are pierced?

1. A

   A. 2 → 3 → 1 → 7 → 4 → 5 → 6

2. B

   B. 2 → 3 → 7 → 1 → 4 → 5 → 6

3. C

   C. 3 → 2 → 1 → 7 → 4 → 5 → 6

4. D

   D. 2 → 1 → 3 → 4 → 7 → 5 → 6

Appeared in: INI-CET EXAM -2026

Explanation

• The correct sequence follows the anatomical path from superficial to deep.
• The needle first pierces the ligaments in the order: Supraspinous (most superficial), Interspinous, and then Ligamentum flavum (deepest ligament).
• After the Ligamentum flavum, the needle enters the Epidural space.
• Following the epidural space, the needle penetrates the three meningeal layers and associated spaces: Dura mater, the potential Subdural space, and finally the Arachnoid mater to enter the subarachnoid space.
• This anatomical order corresponds to the sequence: 2 (Supraspinous ligament) → 3 (Interspinous ligament) → 1 (Ligamentum flavum) → 7 (Epidural space) → 4 (Dura mater) → 5 (Subdural space) → 6 (Arachnoid mater).

Why Other Options Were Wrong

• Option B: This option incorrectly places the Epidural space (7) before the Ligamentum flavum (1).
• Option C: This option incorrectly reverses the order of the first two ligaments. The Supraspinous ligament (2) is more superficial than the Interspinous ligament (3).
• Option D: This option incorrectly places the Ligamentum flavum (1) before the Interspinous ligament (3).

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomy of the vertebral column and procedural steps of lumbar puncture as background academic context rather than a clinical decision trigger.
• Precise knowledge of this anatomical sequence is critical for nurses assisting with or physicians performing a lumbar puncture to ensure the procedure is safe and effective.
• Feeling the characteristic 'pop' as the needle penetrates the ligamentum flavum and dura mater helps confirm the needle's position, reducing the risk of a traumatic tap or procedural failure.
• Complications such as post-dural puncture headache (PDPH), nerve root irritation, or hematoma can arise from incorrect needle placement.

How to Approach the Question

• First, identify the question's core task: to arrange the given anatomical structures in the correct order as they are pierced during a lumbar puncture.
• Mentally visualize or sketch the layers of the back, starting from the skin and moving deeper towards the spinal cord.
• Arrange the ligaments first, from most superficial to deepest: Supraspinous ligament, Interspinous ligament, and Ligamentum flavum.
• Next, place the spaces and meninges in order: Epidural space, Dura mater, Subdural space, and Arachnoid mater.
• Match your anatomical sequence to the numbers provided in the question list (e.g., Supraspinous ligament is #2, Interspinous ligament is #3, etc.).
• Compare your final numbered sequence with the options provided to identify the correct answer.

Concept Tested & Keywords

• Concept Tested: Anatomy of the vertebral column and procedural steps of lumbar puncture.
• Stem keywords: lumbar puncture, spinal needle, anatomical layers, subarachnoid space
• Lead-in keywords: correctly represents the order

Question ID

Qy92Td_M0Et_QOcps_IWG3

Copy ID

Reference Book

E6 Anatomy Applied Ashalatha 4e pp. 423-425, 422-424