A midsagittal T2-weighted MRI of the lumbosacral spine is obtained to exclude a tethered cord in a young adult. At which vertebral level does the conus medullaris normally terminate?

• A Lower border of T12
• B Upper border of S1
• C Lower border of L3
• D Disc between L1 and L2 ✓

Explanation

In adults the spinal cord ends at the L1-L2 intervertebral disc level, so a conus below L2 suggests a tethered cord. In neonates the cord ends lower, near L3, which makes option C tempting if paediatric anatomy is recalled instead. The filum terminale continues inferiorly from the conus to attach on the dorsum of the first coccygeal segment.

Reference: Gray's Anatomy, 42nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.