Advanced Arachnoid Mater Quiz

Q1. Which sequence correctly lists the layers and spaces encountered from the vertebral canal toward the spinal cord?

• Arachnoid, epidural space, dura, pia, subdural space
• Pia, subarachnoid space, arachnoid, dura, epidural space
• Dura, epidural space, pia, arachnoid, subarachnoid space
• Epidural space, dura, potential subdural space, arachnoid, subarachnoid space, pia

Q2. Why does the arachnoid sac extend below the conus medullaris?

• The spinal cord itself continues to S2
• The arachnoid becomes vertebral periosteum at L1
• The meningeal sac continues around CSF and descending neural structures below the cord
• The lumbar cistern lies outside the dura

Q3. Which anatomical fact makes the L3-L4 or L4-L5 region useful for lumbar puncture in adults?

• The dura ends above these levels
• They contain no spinal nerve roots
• They are below the usual end of the spinal cord but within the CSF-filled lumbar cistern
• They are above the cervical enlargement

Q4. What relationship does the arachnoid have to denticulate ligaments?

• They are folds of dura that replace pia
• They lie entirely in the epidural space
• Denticulate ligaments arise from arachnoid and attach to vertebral bodies
• Pial denticulate ligaments cross the subarachnoid region toward the dura

Q5. Why is hemorrhage into the spinal subarachnoid space anatomically different from an epidural collection?

• Subarachnoid blood occupies the CSF space internal to arachnoid, while epidural blood lies external to dura
• Epidural blood lies between pia and spinal cord
• Both collections occupy the same compartment
• Subarachnoid blood lies outside vertebral periosteum

Q6. How does arachnoid mater differ structurally from pia mater at the spinal cord surface?

• Arachnoid is thicker than dura and fused to bone
• Both layers are identical in their relationship to the cord
• Pia lies outside dura
• Arachnoid bridges over contours while pia closely invests the cord

Q7. What is the relationship of the filum terminale internum to the arachnoid sac?

• It passes anterior to vertebral bodies
• It descends within the subarachnoid space to about S2
• It ends at L1 with the conus
• It lies entirely in the epidural space

Q8. Why does the lumbar cistern provide a comparatively safer target for intrathecal access than a level containing the spinal cord?

• It contains no nervous tissue at all
• It contains mobile nerve roots in CSF rather than the spinal cord itself
• It lies outside the meninges
• It is separated from CSF by pia

Q9. What is the anatomical significance of the arachnoid barrier layer?

• It produces vertebral bone
• It connects adjacent intervertebral discs
• It helps separate the CSF compartment from tissues external to the arachnoid
• It forms the spinal cord gray matter

Q10. Which statement best integrates spinal arachnoid anatomy?

• It forms the outer boundary of the spinal CSF compartment and extends with the dural sac to about S2
• It ends with the spinal cord near L1-L2
• It directly adheres to the spinal cord and forms denticulate ligaments
• It lies outside dura and contains epidural fat