mri spine normal position conus tethered radiology education asia radedasia



To determine if the cord is low lying or potentially tethered its important to know what is the lowest level you can see a conus and still call it normal.

The radiology literature varies with a conus at the L2/3 disc or L3 level considered within the normal range.

  • At birth the normal conus will most commonly be at the L1/2 level but can also be at the L2/3 level. The thecal sac is at the S2 level
  • This because the cord grows at a slower rate than the vertebral column.
  • By 2/12 the conus usually lies around the L1/2 level.


This is the statement from the International Society of Pediatric Neurosurgeons.
" Any conus medullaris lying caudal to the mid-body of L2 is considered abnormally low (95% confidence limits) and therefore potentially tethered." (Link to reference in next tab).


spine mri normal position conus tethered radiology education asia

NORMAL: Conus at or above mid L2 is normal at any age (Orange).

ABNORMAL: Conus below mid-L2 abnormal (Green)

We look at all of these topics in more detail in our SPINE MRI Mini Fellowships.

Click on the image below for more information.

#spinemri #cordmri #mrispine

#radedasia #mri #mskmri #radiology

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