• Vertebral bodies grow more quickly than spinal cord during fetal period of <19 weeks MA!
• No significant difference regardless of age!

Inferior-most aspect of conus:

• L1–L2 level: normal (range T12 to L3)
• L2–L3 or higher: in 97.8%
• L3 level: indeterminate (in 1.8%)
• L3–L4 / lower: abnormal
• by 3 month: above inferior endplate of L2 (in 98%)

N.B.: If conus is at / below L3 level, a search should be made for tethering mass, bony spur, thick filum!