In the spinal column,do the letters/numbers reference the vertebrae or the discs? For instance, L4 in lumbar spine. Thanks!?

Question

skeptik · Accepted Answer

Those labels always indicate vertebrae.
Discs would be identified by which vertebrae they are between.

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L4 refers to the 4th Lumbar vertebra.
The disc between the 5th and 6th cervical vertebrae is labelled "C5-6."

Diane A · Answer

The bones, not the discs, that wouldn’t make much sense