In an adult, the spinal cord terminates at which vertebral level, and what structure continues distally from it within the lumbar cistern?

• A Lower border of T12 vertebra, continuing as the cauda equina roots only
• B Upper border of L1 vertebra, continuing as the conus medullaris and filum terminale
• C Lower border of L3 vertebra, continuing as the filum terminale externum
• D Lower border of L1 vertebra, continuing as the filum terminale internum ✓

Explanation

In the adult the conus medullaris ends at the level of the lower border of the first lumbar vertebra, and the filum terminale internum, a pial remnant, descends from it to blend with dura at S2 as the filum terminale externum. At birth the cord reaches approximately L3 because vertebral growth outpaces neural growth. This relationship permits lumbar puncture safely between L3 and L4 or L4 and L5 spinous processes.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.